Center for Turbulence Research

风力发电机wind turbine风电场wind power station wind farm风力发电机组wind turbine generator system WTGS水平轴风力发电机horizontal axis wind turbine垂直轴风力发电机vertical axis wind turbine轮毂（风力发电机）hub (for wind turbine) 机舱nacelle支撑结构support structure for wind turbine关机shutdown for wind turbine正常关机normal shutdown for wind turbine紧急关机emergency shutdown for wind turbine空转idling锁定blocking停机parking静止standstill制动器brake停机制动parking brake风轮转速rotor speed控制系统control system保护系统protection system偏航yawing设计和安全参数design situation设计工况design situation载荷状况load case外部条件external conditions设计极限design limits极限状态limit state使用极限状态serviceability limit states极限限制状态ultimate limit state最大极限状态ultimate limit state安全寿命safe life严重故障catastrophic failure潜伏故障latent fault dormant failure风特性wind characteristic风速wind speed风矢量wind velocity旋转采样风矢量rotationally sampled windvelocity额定风速rated wind speed切入风速cut-in speed切出风速cut-out speed年平均annual average年平均风速annual average wind speed 平均风速mean wind speed极端风速extreme wind speed安全风速survival wind speed参考风速reference wind speed风速分布wind speed distribution瑞利分布RayLeigh distribution威布尔分布Weibull distribution风切变wind shear风廓线风切变律wind profile wind shear law风切变指数wind shear exponent对数风切变律logarithmic wind shear law 风切变幂律power law for wind shear下风向down wind上风向up wind 阵风gust粗糙长度roughness length湍流强度turbulence intensity湍流尺度参数turbulence scale parameter湍流惯性负区inertial sub-range风场wind site测量参数measurement parameters测量位置measurement seat最大风速maximum wind speed风功率密度wind power density风能密度wind energy density日变化diurnal variation年变化annual variation轮毂高度hub height风能wind energy标准大气状态standard atmospheric state风切变影响influence by the wind shear阵风影响gust influence风速频率frequency of wind speed环境environment工作环境operational environment气候climate海洋性气候ocean climate大陆性气候continental climate露天气候open-air climate室内气候indoor climate极端extreme日平均值daily mean极端最高extreme maximum年最高annual maximum年最高日平均温度annual extreme dailymean of temperature月平均温度mean monthly temperature 空气湿度air humidity绝对湿度absolute humidity相对湿度relative humidity降水precipitation雨rain冻雨freezing rain霜淞rime雨淞glaze冰雹hail露dew雾fog盐雾salt fog雷暴thunderstorm雪载snow load标准大气压standard air pressure 平均海平面mean sea level海拔altitude辐射通量radiant flux太阳辐射solar radiation直接太阳辐射direct solar radiation天空辐射sky radiation太阳常数solar constant太阳光谱solar spectrum黑体black body白体white body温室效应greenhouse effect环境温度ambient temperature表面温度surface temperature互联interconnection输出功率output power额定功率rated power最大功率maximum power电网连接点network connection point电力汇集系统power collection system风场电器设备site electrical facilities功率特性power performance静电功率输出net electric power output功率系数power performance自由流风速free stream wind speed扫掠面积swept area轮毂高度hub height测量功率曲线measurement power curve外推功率曲线extrapolated power curve年发电量annual energy production可利用率availability数据组功率特性测试data set for powerperformance measurement精度accuracy测量误差uncertainty in measurement分组方法method of bins测量周期measurement period测量扇区measurement sector日变化diurnal variations浆距角pitch angle距离常数distance constant试验场地test site气流畸变flow distortion障碍物obstacles复杂地形带complex terrain风障wind break声压级sound pressure level声级weighted sound pressure level; sound level 视在声功率级apparent sound power level指向性directivity音值tonality声的基准面风速acoustic reference windspeed标准风速standardized wind speed基准高度reference height基准粗糙长度reference roughness length基准距离reference distance掠射角grazing angle风轮风轮wind rotor风轮直径rotor diameter风轮扫掠面积rotor swept area风轮仰角tilt angle of rotor shaft风轮偏航角yawing angle of rotor shaft风轮额定转速rated turning speed of rotor风轮最高转速maximum turning speed ofrotor风轮尾流rotor wake尾流损失wake losses风轮实度rotor solidity实度损失solidity losses叶片数number of blades叶片blade等截面叶片constant chord blade变截面叶片variable chord blade叶片投影面积projected area of blade叶片长度length of blade叶根root of blade叶尖tip of blade叶尖速度tip speed浆距角pitch angle翼型airfoil前缘leading edge后缘tailing edge几何弦长geometric chord of airfoil平均几何弦长mean geometric of airfoil 气动弦线aerodynamic chord of airfoil翼型厚度thickness of airfoil翼型相对厚度relative thickness of airfoil 厚度函数thickness function of airfoil中弧线mean line弯度degree of curvature翼型族the family of airfoil弯度函数curvature function of airfoil叶片根梢比ratio of tip-section chord to root-section chord 叶片展弦比aspect ratio叶片安装角setting angle of blade叶片扭角twist of blade叶片几何攻角angle of attack of blade叶片损失blade losses叶尖损失tip losses颤振flutter迎风机构orientation mechanism调速机构regulating mechanism风轮偏测式调速机构regulatingmechanism of turning wind rotor out ofthe wind sideward变浆距调速机构regulating mechanism byadjusting the pitch of blade整流罩nose cone顺浆feathering阻尼板spoiling flap风轮空气动力特性aerodynamiccharacteristics of rotor叶尖速度比tip-speed ratio额定叶尖速度比rated tip-speed ratio升力系数lift coefficient阻力系数drag coefficient推或拉力系数thrust coefficient偏航系统滑动制动器sliding shoes偏航yawing主动偏航active yawing被动偏航passive yawing偏航驱动yawing driven解缆untwist塔架tower独立式塔架free stand tower拉索式塔架guyed tower塔影响效应influence by the tower shadow<<功率特性测试>>功率特性power performance净电功率输出net electric power output 功率系数power coefficient自由流风速free stream wind speed扫掠面积swept area测量功率曲线measured power curve外推功率曲线extrapolated power curve 年发电量annual energy production数据组data set可利用率availability精度accuracy 测量误差uncertainty in measurement分组方法method of bins测量周期measurement period测量扇区measurement sector距离常数distance constant试验场地test site气流畸变flow distortion复杂地形地带complex terrain风障wind break声压级sound pressure level声级weighted sound pressure level视在声功率级apparent sound power level指向性directivity音值tonality声的基准风速acoustic reference windspeed标准风速standardized wind speed基准高度reference height基准粗糙长度reference roughness基准距离reference distance掠射角grazing angle比恩法method of bins标准误差standard uncertainty风能利用系数rotor power coefficient力矩系数torque coefficient额定力矩系数rated torque coefficient起动力矩系数starting torque coefficient最大力矩系数maximum torque coefficient过载度ratio of over load风力发电机组输出特性outputcharacteristic of WTGS调节特性regulating characteristics平均噪声average noise level机组效率efficiency of WTGS使用寿命service life度电成本cost per kilowatt hour of the electricity generated by WTGS发电机同步电机synchronous generator异步电机asynchronous generator感应电机induction generator转差率slip瞬态电流transient rotor笼型cage绕线转子wound rotor绕组系数winding factor换向器commutator集电环collector ring 换向片commutator segment励磁响应excitation response制动系统制动系统braking制动机构brake mechanism正常制动系normal braking system紧急制动系emergency braking system空气制动系air braking system液压制动系hydraulic braking system电磁制动系electromagnetic brakingsystem机械制动系mechanical braking system辅助装置auxiliary device制动器释放braking releasing制动器闭合brake setting液压缸hydraulic cylinder溢流阀relief valve泻油drain齿轮马达gear motor齿轮泵gear pump电磁阀solenoid液压过滤器hydraulic filter液压泵hydraulic pump液压系统hydraulic system油冷却器oil cooler压力控制器pressure control valve压力继电器pressure switch减压阀reducing valve安全阀safety valve设定压力setting pressure切换switching旋转接头rotating union压力表pressure gauge液压油hydraulic fluid液压马达hydraulic motor油封oil seal刹车盘brake disc闸垫brake pad刹车油brake fluid闸衬片brake lining传动比transmission ratio齿轮gear齿轮副gear pair平行轴齿轮副gear pair with parallel axes 齿轮系train of gears行星齿轮系planetary gear train小齿轮pinion大齿轮wheel , gear 主动齿轮driving, gear从动齿轮driven gear行星齿轮planet gear行星架planet carrier太阳轮sun gear内齿圈ring gear外齿轮external gear内齿轮internal内齿轮副internal gear pair增速齿轮副speed increasing gear增速齿轮系speed increasing gear train中心距center distance增速比speed increasing ratio齿面tooth flank工作齿面working flank非工作齿面non-working flank模数module齿数number of teeth啮合干涉meshing interference齿廓修行profile modification , profilecorrection啮合engagement, mesh齿轮的变位addendum modification ongears变位齿轮gears with addendummodification圆柱齿轮cylindrical gear直齿圆柱齿轮spur gear斜齿圆柱齿轮helical gear single-helicalgear节点pitch point节圆pitch circle齿顶圆tip circle齿根圆root circle直径和半径diameter and radius 齿宽face width齿厚tooth thickness压力角pressure angle圆周侧隙circumferential backlash 蜗杆worm蜗轮worm wheel联轴器coupling刚性联轴器rigid coupling万向联轴器universal coupling安全联轴器security coupling齿tooth齿槽tooth space斜齿轮helical gear 人字齿轮double-helical gear齿距pitch法向齿距normal pitch轴向齿距axial pitch齿高tooth depth输入角input shaft输出角output shaft柱销pin柱销套roller行星齿轮传动机构planetary gear drivemechanism中心轮center gear单级行星齿轮系single planetary geartrain柔性齿轮flexible gear刚性齿轮rigidity gear柔性滚动轴承flexible rolling bearing输出联接output coupling刚度rigidity扭转刚度torsional rigidity弯曲刚度flexural rigidity扭转刚度系数coefficient of torsional起动力矩starting torque传动误差transmission error传动精度transmission accuracy固有频率natural frequency弹性联接elastic coupling刚性联接rigid coupling滑块联接Oldham coupling固定联接integrated coupling齿啮式联接dynamic coupling花键式联接splined coupling牙嵌式联接castellated coupling 径向销联接radial pin coupling周期振动periodic vibration随机振动random vibration峰值peak value临界阻尼critical damping阻尼系数damping coefficient阻尼比damping ratio减震器vibration isolator振动频率vibration frequency幅值amplitude位移幅值displacement amplitude 速度幅值velocity amplitude加速度幅值acceleration amplitude 控制与监控系统远程监视telemonitoring 协议protocol实时real time单向传输simplex transmission半双工传输half-duplex transmission双工传输duplex transmission前置机front end processor运输终端remote terminal unit调制解调器modulator-demodulator数据终端设备data terminal equipment接口interface数据电路data circuit信息information状态信息state information分接头位置信息tap position information监视信息monitored information设备故障信息equipment failureinformation告警alarm返回信息return information设定值set point value累积值integrated total integrated value瞬时测值instantaneous measured计量值counted measured meteredmeasured metered reading确认acknowledgement信号signal模拟信号analog signal命令command字节byte位bit地址address波特baud编码encode译码decode代码code集中控制centralized control可编程序控制programmable control 微机程控minicomputer program模拟控制analogue control数字控制digital control强电控制strong current control弱电控制weak current control单元控制unit control就地控制local control联锁装置interlocker模拟盘analogue board配电盘switch board控制台control desk 紧急停车按钮emergency stoppush-button限位开关limit switch限速开关limit speed switch有载指示器on-load indicator屏幕显示screen display指示灯display lamp起动信号starting signal公共供电点point of common coupling闪变flicker数据库data base硬件hardware硬件平台hardware platform层layer level class模型model响应时间response time软件software软件平台software platform系统软件system software自由脱扣trip-free基准误差basic error一对一控制方式one-to-one control mode一次电流primary current一次电压primary voltage二次电流secondary current二次电压secondary voltage低压电器low voltage apparatus额定工作电压rated operational voltage额定工作电流rated operational current运行管理operation management安全方案safety concept外部条件external conditions失效failure故障fault控制柜control cabinet冗余技术redundancy正常关机normal shutdown失效-安全fail-safe排除故障clearance空转idling外部动力源external power supply锁定装置locking device运行转速范围operating rotational speed range临界转速activation rotational speed最大转速maximum rotational speed过载功率over power临界功率activation power 最大功率maximum power短时切出风速short-term cut-out windspeed外联机试验field test with turbine试验台test-bed台架试验test on bed防雷系统lighting protection system外部防雷系统external lighting protectionsystem内部防雷系统internal lighting protectionsystem等电位连接equipotential bonding接闪器air-termination system引下线down-conductor接地装置earth-termination system接地线earth conductor接地体earth electrode环形接地体ring earth external基础接地体foundation earth electrode等电位连接带bonding bar等电位连接导体bonding conductor保护等级protection lever防雷区lighting protection zone雷电流lighting current电涌保护器surge suppressor共用接地系统common earthing system接地基准点earthing reference points持续运行continuous operation持续运行的闪变系数flicker coefficient forcontinuous operation闪变阶跃系数flicker step factor最大允许功率maximum permitted最大测量功率maximum measured power 电网阻抗相角network impedance phase angle正常运行normal operation功率采集系统power collection system额定现在功率rated apparent power额定电流rated current额定无功功率rated reactive power停机standstill起动start-up切换运行switching operation扰动强度turbulence intensity电压变化系数voltage change factor风力发电机端口wind turbine terminals风力发电机最大功率maximum power of wind turbine 风力发电机停机parked wind turbine安全系统safety system控制装置control device额定载荷rated load周期period相位phase频率frequency谐波harmonics瞬时值instantaneous value同步synchronism振荡oscillation共振resonance波wave辐射radiation衰减attenuation阻尼damping畸变distortion电electricity电的electric静电学electrostatics电荷electric charge电压降voltage drop电流electric current导电性conductivity电压voltage电磁感应electromagnetic induction励磁excitation电阻率resistivity导体conductor半导体semiconductor电路electric circuit串联电路series circuit电容capacitance电感inductance电阻resistance电抗reactance阻抗impedance传递比transfer ratio交流电压alternating voltage 交流电流alternating current 脉动电压pulsating voltage脉动电流pulsating current直流电压direct voltage直流电流direct current瞬时功率instantaneous power 有功功率active power无功功率reactive power有功电流active current 无功电流reactive current功率因数power factor中性点neutral point相序sequential order of the phase电气元件electrical device接线端子terminal电极electrode地earth接地电路earthed circuit接地电阻resistance of an earthedconductor绝缘子insulator绝缘套管insulating bushing母线busbar线圈coil螺纹管solenoid绕组winding电阻器resistor电感器inductor电容器capacitor继电器relay电能转换器electric energy transducer电机electric machine发电机generator电动机motor变压器transformer变流器converter变频器frequency converter整流器rectifier逆变器inverter传感器sensor耦合器electric coupling放大器amplifier振荡器oscillator滤波器filter半导体器件semiconductor光电器件photoelectric device 触头contact开关设备switchgear控制设备control gear闭合电路closed circuit断开电路open circuit通断switching联结connection串联series connection并联parallel connection星形联结star connection三角形联结delta connection 主电路main circuit辅助电路auxiliary circuit控制电路control circuit信号电路signal circuit保护电路protective circuit换接change-over circuit换向commutation输入功率input power输入input输出output负载load加载to load充电to charge放电to discharge有载运行on-load operation空载运行no-load operation开路运行open-circuit operation短路运行short-circuit operation满载full load效率efficiency损耗loss过电压over-voltage过电流over-current欠电压under-voltage特性characteristic绝缘物insulant隔离to isolate绝缘insulation绝缘电阻insulation resistance品质因数quality factor泄漏电流leakage current闪烙flashover短路short circuit噪声noise极限值limiting value额定值rated value额定rating环境条件environment condition 使用条件service condition工况operating condition额定工况rated condition负载比duty ratio绝缘比insulation ratio介质试验dielectric test常规试验routine test抽样试验sampling test验收试验acceptance test投运试验commissioning test 维护试验maintenance test加速accelerating特性曲线characteristic额定电压rated voltage额定电流rated current额定频率rated frequency温升temperature rise温度系数temperature coefficient端电压terminal voltage短路电流short circuit current可靠性reliability有效性availability耐久性durability维修maintenance维护preventive maintenance工作时间operating time待命时间standby time修复时间repair time寿命life使用寿命useful life平均寿命mean life耐久性试验endurance test寿命试验life test可靠性测定试验reliability determinationtest现场可靠性试验field reliability test加速试验accelerated test安全性fail safe应力stress强度strength试验数据test data现场数据field data电触头electrical contact主触头main contact击穿breakdown耐电压proof voltage放电electrical discharge透气性air permeability电线电缆electric wire and cable电力电缆power cable通信电缆telecommunication cable油浸式变压器oil-immersed type transformer干式变压器dry-type transformer自耦变压器auto-transformer有载调压变压器transformer fitted with OLTC空载电流non-load current 阻抗电压impedance voltage电抗电压reactance voltage电阻电压resistance voltage分接tapping配电电器distributing apparatus控制电器control apparatus开关switch熔断器fuse断路器circuit breaker控制器controller接触器contactor机械寿命mechanical endurance电气寿命electrical endurance旋转电机electrical rotating machine直流电机direct current machine交流电机alternating current machine同步电机synchronous machine异步电机asynchronous machine感应电机induction machine励磁机exciter饱和特性saturation characteristic开路特性open-circuit characteristic负载特性load characteristic短路特性short-circuit characteristic额定转矩rated load torque规定的最初起动转矩specifies breakawaytorque交流电动机的最初起动电流breakawaystarting current if an a.c.同步转速synchronous speed转差率slip短路比short-circuit ratio同步系数synchronous coefficient空载no-load系统system触电；电击electric block正常状态normal condition接触电压touch voltage跨步电压step voltage对地电压voltage to earth触电电流shock current残余电流residual current安全阻抗safety impedance安全距离safety distance安全标志safety marking安全色safety color中性点有效接地系统system with effectively earthed neutral 检修接地inspection earthing工作接地working earthing保护接地protective earthing重复接地iterative earth故障接地fault earthing过电压保护over-voltage protection过电流保护over-current protection断相保护open-phase protection防尘dust-protected防溅protected against splashing防滴protected against dropping water防浸水protected against the effects ofimmersion过电流保护装置over-current protectivedevice保护继电器protective relay接地开关earthing switch漏电断路器residual currentcircuit-breaker灭弧装置arc-control device安全隔离变压器safety isolatingtransformer避雷器surge attester ; lightning arrester保护电容器capacitor for voltageprotection安全开关safety switch限流电路limited current circuit振动vibration腐蚀corrosion点腐蚀spot corrosion金属腐蚀corrosion of metals化学腐蚀chemical corrosion贮存storage贮存条件storage condition运输条件transportation condition空载最大加速度maximum bare table acceletation电力金具悬垂线夹suspension clamp耐张线夹strain clamp挂环link挂板clevis球头挂环ball-eye球头挂钩ball-hookU型挂环shackleU型挂钩U-bolt联板yoke plate牵引板towing plate 挂钩hook吊架hanger调整板adjusting plate花篮螺栓turn buckle接续管splicing sleeve补修管repair sleeve调线线夹jumper clamp防振锤damper均压环grading ring屏蔽环shielding ring间隔棒spacer重锤counter weight线卡子guy clip心形环thimble设备线夹terminal connectorT形线夹T-connector硬母线固定金具bus-bar support母线间隔垫bus-bar separetor母线伸缩节bus-bar expansion外光检查visual ins振动试验vibration tests老化试验ageing tests冲击动载荷试验impulse load tests耐腐试验corrosion resistance tests棘轮扳手ratchet spanner专用扳手special purpose spanner万向套筒扳手flexible pliers可调钳adjustable pliers夹线器conductor holder电缆剪cable cutter卡线钳conductor clamp单卡头single clamp双卡头double clamp安全帽safety helmet安全带safety belt绝缘手套insulating glove绝缘靴insulating boots护目镜protection spectacles 缝焊机seam welding machine。

Effects of irrigation on water balance,yield and WUE of winter wheat in the North China PlainHong-Yong Sun a,b,c,*,Chang-Ming Liu a,b,Xi-Ying Zhang a,Yan-Jun Shen a,Yong-Qiang Zhang aa Center for Agricultural Resources Research,Institute of Genetic and Developmental Biology,CAS,286Huaizhong Road,Shijiazhuang050021,Hebei Province,Chinab Institute of Geographical Sciences and Natural Resources Research of CAS,Beijing100101,Chinac Graduate School of Chinese Academy of sciences,Beijing100049,China1.IntroductionWinter wheat(Triticum aestivum L.)is a major crop in theNorth China Plain(NCP)and its food production accounts forabout71%of wheat production in China.However,water isthe most important limiting factor for wheat production.Inthe winter wheat season precipitation ranges from50mm indry years to150mm in wet years,with an average annualprecipitation of115.9mm.The total water consumption isabout453mm for winter wheat without water deficit,whichgreatly exceeds precipitation(Liu et al.,2002).To achievehigher grain yields(GY),farmers in this region pumpgroundwater to irrigate winter wheat to offset the ET deficit.More than80%of the water resources from surface runoffand groundwater have been exploited for irrigation.Theexcessive exploitation of groundwater resources fromshallow and deep aquifers in this region has caused thewater table to fall and created many other environmentalproblems within the plain(Liu and Wei,1989).The ground-water table is falling steadily at the rate of about1m per yearand the main factors leading to this fall are the expandingwheat area which is irrigated with groundwater and the lowwater-use efficiency(WUE)of crops(Hu et al.,2002).So it isnow very important to control or decrease the falling rate ofgroundwater table by reducing the amount of irrigation inkeeping with high GY.a g r i c u l t u r a l w a t e r m a n a g e m e n t85(2006)211–218a r t i c l e i n f oArticle history:Accepted30April2006Published on line15June2006Keywords:Triticum aestivum L.EvapotranspirationIrrigationWater-use efficiencyGrain yielda b s t r a c tLimited precipitation restricts yield of winter wheat grown in the North China Plain(NCP).Irrigation experiments were conducted during different growing stages of winter wheat(Triticum aestivum L.)at Luancheng agro-ecology systems station of the Chinese Academy ofSciences during1999/2000,2000/2001and2001/2002to identify suitable irrigation schedulesfor winter wheat.The aim was also to develop relationships between seasonal amounts ofirrigation and yield,water-use efficiency(WUE),irrigation water-use efficiency(WUEi),netwater-use efficiency(WUEet)and evapotranspiration(ET).A comparison of irrigationschedules for wheat suggested that for maximum yield in the NCP,300mm is an optimalamount of irrigation,corresponding to an ET value of426mm.Results showed that withincreasing ET,the irrigation requirements of winter wheat increase as do soil evaporationbut excessive amounts of irrigation can decrease grain yield,WUE,and WUEi.These resultsindicate that excessive irrigation might not produce greater yield or optimal economicbenefit,thus,suitable irrigation schedules must be established.#2006Elsevier B.V.All rights reserved.*Corresponding author.Tel.:+8631185814362;fax:+8631185815093.E-mail addresses:hysun@,sunhy.04b@(H.-Y.Sun).a v a i l ab l e a t w w w.s ci e nc e di r e ct.comj o u r n a l h o m e p a g e:w w w.e l s e v i e r.c o m/l o c a t e/a g w a t0378-3774/$–see front matter#2006Elsevier B.V.All rights reserved.doi:10.1016/j.agwat.2006.04.008The effects of irrigation on crop production are usually quantified using crop water production functions which relate crop yield to amounts of water applied(Yaron and Bresler, 1983;English,1990;English and Raja,1996).The rational irrigation can significantly increase the GY(Hagan et al.,1967; Gajri et al.,1997;Huang et al.,2004).Hagan et al.(1967)also asserted that excessive irrigation delays the maturity,harvest-ing and decreased GY.Jin et al.(1999)reported that excessive irrigation led to a decrease of crop WUE and that effective deficit irrigation may result in higher production and WUE.On the contrary,Olesen et al.(2000)showed that the effect of irrigation on wheat yield was almost solely due to increased transpiration,while WUE and harvest index remained unaffected.Kang et al.(2002)indicated that the responses of grain yield and WUE to irrigation varied considerably due to differences in soil water contents and irrigation schedules. Singh et al.(1991)concluded that the impact of limited irrigation and soil water deficit on crop yield or WUE depends on the particular growth stage of the crop.Many studies have shown that the relationship between wheat yield and seasonal ET is linear(Singh,1981;Mogenson et al.,1985;Steiner et al.,1985;Musick et al.,1994;Zhang and Oweis,1999;Zhang et al.,1999a,b).Though,Aggarwal et al. (1986)showed the curvilinear result,Kang et al.(2002)reported that relationships between seasonal ET and grain yield or WUE could be described by quadratic functions,While relationships between ET and GY have been widely used for water-saving purposes in water deficit areas as a guideline for irrigation, they cannot explain the effects of timing applications.So there has been an ongoing effort to reveal relationships between GY of winter wheat and soil water balance(especially irrigation) and water-use efficiency.In this paper we discuss the effects of irrigation at different growth stages on WUE,GY,ET and its components.On the basis of our results,guidelines are provided for farmers and irrigation agencies to achieve water-saving irrigation practice and efficient use of water resources for wheat production in the NCP.So objectives of this study are:(1)To investigate the significance of irrigation as a compo-nents of soil water balance.(2)To discover the effects of irrigation on ET,soil evaporation(E),E/ET and GY.(3)To interpret the impact of irrigation on irrigation water-useefficiency(WUEi),net water-use efficiency(WUEet)and WUE.2.Materials and methodsFrom1999to2002,experiments were performed at Luancheng experimental station(378530N,1148410E,with elevation at 50.1m),located in the high-yielding area of NCP and being one of the agricultural ecosystem stations of the Chinese Academy of Sciences.Local soil characteristics and parameters are shown in Table1,indicating fertile topsoil and plenty of organic matter in the loam soil.The climate is of the temperate semi-arid monsoon type,with a mean annual temperature of 12.28C,mean annual global radiation of5240MJ/m2,mean annual precipitation of475.4mm,and about75%of which occurs from late June to September.The distribution of rainfall in the three growing seasons is shown in Table2.The difference of total rainfall in the different growing seasons was larger,while the distribution also was uneven in the different growing stage and little rainfall occurred between December and March.There was about20mm rainfall before the harvest in2000–2001growing season.There are sixteen5mÂ10m plots divided by concrete walls which were built in1995forfive treatments of irrigation schedules.The concrete walls are24.5cm thick and extend 1.5m beneath the surface,in accordance with specifications set by the Food and Agricultural Organization.Winter wheat,Gaoyou503,was sown at the beginning of October and harvested in mid-June of the following year.The seed rate was150kg haÀ1,with a20cm row width.Before sowing,chemical fertilizers of N and P at rate of130kg haÀ1N and160kg haÀ1P2O5were applied and cultivation was done to mix the fertilizers with top soil manually.Each plot was also irrigated with about80mm of water to ensure better seedling establishment.The straw of previous crop(maize)was removed and there were not any straw or plant residues to mulch the plots.Other management practice was consistent with typicalfield conditions.Thefive irrigation schedules are shown in Table3and each treatment was replicated three times(treatment E had four replicates).a g r i c u l t u r a l w a t e r m a n a g e m e n t85(2006)211–2182121Soil depth0–20cm20–35cm35–65cm65–90cm90–145cm145–170cm170–190cm Texture Sandy loam Sandy loam Light loam Medium loam Light clay Light clay Sandy clay BD(g/cm3) 1.41 1.51 1.47 1.51 1.54 1.64 1.59FC(vol.%)36.434.933.334.334.439.038.1WP(vol.%)9.611.413.913.913.013.916.4BD:bulky density;FC:field capacity;WP:wilting point.2Seasons October November December January February March April May June Total rainfall 1999–200020.7 6.10.211.400.8 2.511.8053.5 2000–200153.78.408.1 6.90.523.320.218.2139.3 2001–20029.4100.4 1.20 5.530.145.7 6.3108.6Volumetric soil moisture was measured with a neutron probe(IH-II,Institute of Hydrology,UK)in access tubes located at the center of each of the16experimental plots down to 180cm at20cm intervals at about every5days.Precipitation was recorded at a standard weather station about100m from the plots.The irrigation application to each plot was measured using a water meter which was installed at the hydrant of a low-pressure tube water transportation system.GY of winter wheat was sampled from the3mÂ8m portion in the central area of each plot and the plant sampling measurements were performed in the surrounding area of each plots.Biomass was calculated by weighing air-dried harvest samples.Soil evaporation(E)beneath the winter wheat canopy was estimated by daily weighing of three micro-lysimeters(MLS), which were placed between two rows.MLS contain small isolated volumes of bare soil mountedflush with or slightly above the soil surface(Daamen et al.,1993)and these were weighed daily(or more frequently)to determine water loss using electronic balances with0.001kg precision.The MLS cylinders were150mm long,120mm diameter and with a 2mm thick wall.They were constructed of PVC with the bottom beingfixed using plastic adhesive tape.To keep soil moisture in the MLS in agreement with outside conditions,the original soil in the instruments was changed every2or3days, and after rain or irrigation it was changed immediately(Sun et al.,2002).ET was calculated using the soil water balance equation for the growing season and for individual growth periods as follows:ET¼SWDþPþIÀDþW gÀR(1)where ET is evapotranspiration(mm),SWD the soil water depletion in the measured soil depth during the growing stage, P rainfall(mm),I irrigation applications(mm),D soil water drainage(mm),R surface runoff(mm),W g water used by crop through capillary rise from groundwater(mm).When the groundwater table is lower than4m below the ground surface, W g is negligible(Liu and Wei,1989).There usually is no runoff in the area,so R was also ignored.Drainage was estimated as follows using a recharge coefficient(a)multiplied by the amount of irrigation or the effective rainfall(mm):D¼a I(2)The recharge coefficient(a)depends on soil texture and on the amount of irrigation.The coefficient ranges from0.1for clay soil to0.3for sandy soil,which was determined by monitoring the change of groundwater table after irrigation was applied in a large area(Ministry of Geology and Mineral Resources,1986).Values of a was taken to be0.1for irrigation amounts<90mm,0.15for irrigation between90and250mm, and0.2for irrigation250mm for the soils of this experimental condition.Water-use efficiency was calculated as(Hussain et al., 1995):WUE¼GYET(3)where WUE(kg mÀ3)is the water-use efficiency for the GY (kg mÀ2)and ET(m)is calculated as in Eq.(1).Net water-use efficiency(WUEet)and irrigation water-use efficiency(WUEi)can be written as follows,respectively(Bos, 1985):WUEet¼ðY iÀY dÞðET iÀET dÞ(4) WUEi¼ðGY iÀGY dÞI i(5)where GY i is the yield and ET i is the ET for irrigation level i, GY d is the grain yield and ET d is the ET for an equivalent dry land or rain-fed plot,and I i is the amount of irrigation applied for level i.In most cases,GY d would be zero or small in fully rain-fed conditions.In our experiment,treatment E is not irrigated after spring so this is regarded as a rain-fed treat-ment.WUEet can be regarded as net ET efficiency because it is based on the yield produced above the rain-fed yield divided by net ET difference for the irrigated crop.In our experiments all treatments were irrigated before winter dormancy so that the winter wheat could survive the cold winter.Analysis of variance(ANOVA)was used to test the difference in ET,I,SWD,E and WUE between different treatments.Mean comparisons were made by the LSD(the least significant difference)method with P<0.05.The ana-lyses were conducted using the SPSS program.3.Results and discussion3.1.Irrigation andfield water balanceIrrigation is one of the key factors affecting whether actual ET is close to the potential ponents of soil water balance as influenced by different irrigation schedules in the threea g r i c u l t u r a l w a t e r m a n a g e m e n t85(2006)211–2182133Treatments Winter dormancy Recovering Stem-elongation Heading Grain-fillingA 1.0–0.80.80.8B 1.00.8–0.80.8C 1.00.80.80.8–D 1.0 1.0 1.0 1.0 1.0E 1.0––––a‘‘–’’shows no irrigation applied;1.0and0.8means the ratio of u/uFC.crop seasons are shown in Table 4.ET of different treatments ranged from 200to 460mm in 1999/2000,240to 440mm in 2000/2001and 260to 445mm in 2001/2002.The most irrigated treatment D gave the maximum ET,and the least irrigated treatment E had the lowest ET.The results indicated ET of winter wheat was greatly affected by irrigation application.The SWD in Table 4showed the depletion of soil water storage during the whole growing season of winter wheat.It ranged from 16to 82.9mm.The SWD for the D treatment was the least among all the treatments,indicating irrigation could meet the needs of winter wheat.The SWD for the C treatment was the most,because it consumed the largest water amount during the grain-filling period.However,the SWD for the least irrigated treatment E was not the largest.The reason might be that under this treatment winter wheat was in serious water stress condition and both its canopy and its underground root system were restricted.The root might not be able to go deep to uptake soil water stored there that limited its soil water utilization.The SWD of treatments A and B was not significant difference (P =0.05).Percolation from the root zone was also one of the important components in soil water balance.The difference of drainage amount between treatments depended on the amount of total irrigation.Treatment D had the largestdrainage amount and treatment E had the least amount.The difference between irrigation and drainage would directly influenced the groundwater table declining rate in the region.Fig.1shows the relationships between irrigation and ET.They were linearly correlated with the increasing in irrigation,ET increased.ET was driven by meteorological factors,crop factors and soil factors and which is not only water consuming process but also an energy consuming process.In order to clarify the effects of irrigation on ET,regression analysis was carried out.Significant relationship (P =0.01)existed between irrigation water amount with ET and the relations were described with the following equation:ET ¼0:7361I þ178:88;R 2¼0:8893(7)where ET is evapotranspiration (mm)and I the total irrigation water applied in the whole growing period of winter wheat (mm).3.2.Impacts of irrigation on evaporation and transpirationET,the process by which water moves into the atmosphere through plants and soil,consists of soil evaporation (E )and plant transpiration (T ),is expressed by ET ¼E þT(8)Table 5shows the evaporation beneath the winter wheat canopy (Table 5).There were significant differences (P =0.05)in soil evaporation among the treatments.The evaporation in D treatments was the highest and in E treatment was the lowest.The reason might be that under larger irrigation amounts soil surface was wetter which promoted higher soil evaporation.The biggest differences between the highest and the lowest soil evaporation were 32mm in 1999/2000,34mm in 2000/2001and 42mm in 2001/2002.Generally with the increase in irrigation,E was increased.But the evaporation beneath winter wheat canopy among the different irrigationa g r i c u l t u r a l w a t e r m a n a g e m e n t 85(2006)211–218214419992002YearsTreatmentsRainfall (mm)Irrigation (mm)SWD (mm)Drainage (mm)ET (mm)1999–2000A 53.5284.565.7Æ15.2ab 20.5383.2Æ11.7bc B 323.961.1Æ5.8ab 17.1421.4Æ20.6b C 247.982.9Æ19.9a 10.8373.4Æ21.4c D 404.842.2Æ12.6bc 36.5464.0Æ35.1a E 80.066.5Æ18.5ab 8.0192.0Æ16.5d 2000–2001A 139.3272.716.0Æ8.8ns 11.0417.0Æ70.3a B 234.016.0Æ8.0ns 20.5368.8Æ11.2a C 230.033.3Æ17.3ns 17.1385.5Æ29.5a D 308.720.4Æ15.0ns 24.7443.7Æ70.8a E 80.030.0Æ7.6ns 8.0241.3Æ22.5b 2001–2002A 108.6249.358.5Æ10.3b 18.6397.9Æ36.4b B 247.571.1Æ20.9ab 20.7406.4Æ16.1ab C 250.782.4Æ5.9a 10.7431.0Æ11.8ab D 354.113.7Æ5.3c 31.4444.9Æ25.5a E80.079.1Æ11.7a8.0259.7Æ11.7cLetters indicate statistical significance at P =0.05level within the same column,and ‘‘a’’,‘‘b’’,‘‘c’’and so on show the statistical difference from the highest to the lowest.SWD represents soil profile depletion.aValues are means of three replicates (treatment E with fourreplicates).Fig.1–Relationships between evapotranspiration (ET)and irrigation in three crop seasons.level was similar between stem elongation and maturation for the plant factors(Sun et al.,2004).The ratios of E to ET were different and they ranged from 30%to56%in1999/2000,32%to45%in2000/2001and24%to 38%in2001/2002,respectively.E/ET of treatment E was the highest and the average ratio was about46%in three seasons. The average ratios of the other treatments ranged from31.3% to33.1%.High ratio of E/ET in treatment E was due to its smaller canopy coverage,and especially after rainfall E was quite bigger than that of other treatments.The above results indicated that E/ET for the whole growing period of winter wheat was more than30%with the highest ratio of E/ET occurring at the beginning of the growing season,after stem-elongation;it was getting less due to the canopy development.However,the absolute amount of evaporation was still large at the growing phases when plant transpiration consumed most of water(Liu et al.,2002).So how to decrease the soil evaporation and make it available for transpiration through the plant is an important way to save water.Some experiments conducted at the station showed that straw mulching was an effective way to reduce soil evapora-tion(Zhang et al.,1994,2005).But for winter crops the existing of straw on soil surface slowed down soil temperature rising after winter,which affected crop growth(Chen et al.,2005). Another method to reduce soil evaporation was to hoe the soil surface that cut down the soil moisture transfer to soil surface. According to Zhang et al.(1998),the best time to hoe soil was in spring when winter wheat begins to recover after winter dormancy.a g r i c u l t u r a l w a t e r m a n a g e m e n t85(2006)211–2182155Seasons Treatments Evapotranspiration(ET)(mm)Evaporation(E)(mm)Transpiration(T)(mm)E/ET(%)1999–2000A383.2129.9c253.333.9c B421.4134.9b286.532.0bC373.4128.9c244.534.5dD464.0140.4a323.630.3eE192.0108.0d84.056.3a2000–2001A417.0135.7b281.332.5d B368.8138.1b230.737.4bC385.5137.7b247.835.7cD443.7143.0a300.732.2eE241.3108.7c132.645.1a2001–2002A397.9121.9b276.030.6bc B406.4121.1b285.329.8cC431.0104.8c326.224.3dD444.9139.9a305.031.4bE259.797.9d161.937.7aLetters indicate statistical significance at P=0.05level within the same column,with‘‘a’’,‘‘b’’,‘‘c’’and so on showing the statistical difference from the highest to the lowest.a Values are means of three replicates(treatment E with four replicates).6Year Treatment Irrigation(mm)Grain yield(kg haÀ1)WUEi(kg mÀ3)WUEet(kg mÀ3)WUE(kg mÀ3)1999–2000A284.55467Æ179a0.67ab0.50b 1.43bc B323.95487Æ252a0.60b0.54ab 1.31cC247.95584Æ151a0.82a0.49c 1.50bD404.85306Æ64a0.43c0.59a 1.14dE80.03552Æ172b–– 1.83a2000–2001A272.74893Æ172a0.57ab0.42ns 1.19ab B234.04965Æ142a0.54ab0.35ns 1.33abC230.05177Æ276a0.80a0.37ns 1.34abD308.74972Æ96a0.53b0.46ns 1.12bE80.03328Æ80b–– 1.38a2001–2002A249.34299Æ174a0.31ab0.35ns 1.08b B247.54431Æ79a0.37a0.36ns 1.09bC250.74417Æ165a0.36a0.40ns 1.03bD354.14333Æ137a0.23b0.42ns0.97bcE80.03526Æ52b–– 1.36aLetters indicate statistical significance at P=0.05level within the same column,with‘‘a’’,‘‘b’’,‘‘c’’and so on showing the statistical difference from the highest to the lowest.a Values are means of three replicates(treatment E with four replicates).3.3.Irrigation and WUETable 6shows the WUEi,WUEet,and WUE of the different irrigation treatments in the three winter wheat seasons from 1999to 2002.WUEi ranged from 0.23to 0.82kg m À3and the trend was similar among the treatments for the three seasons and their difference was significant at P =0.05The WUEi of the most irrigated treatment D was the lowest and the moderately irrigated treatment C was the highest.For treatment C the water deficit occurred during grain-filling when winter wheat was not sensitive to water stress (Zhang et al.,1999a,b,2003).No significant difference was found between treatments A and B.This result was consistent with the findings of Li et al.(1995)in the Loess Plateau,who reported that WUEi decreased with increasing in irrigation and because grain yield did not increase linearly with irrigation,excessive irrigation even decreased grain production.WUEet ranged from 0.35to 0.59kg m À3with treatment D at the highest.Increasing in the amounts of irrigation appeared not to increase grain yield.The results were similar in 2000/2001and 2001/2002seasons and there was not any significant difference among the treatments when seasonal rainfall was high.The results indicated that the amount of rainfall affected WUEet.WUE ranged from 0.97to 1.83kg m À3.It was similar to other values reported for winter wheat.Zhang et al.(1998)reported WUE values for winter wheat between 0.93and 1.51kg m À3and Wang et al.(2001)found that WUE was between 0.70and 1.30kg m À3in the NCP.The WUE of treatment E was the highest and the lowest WUE occurred in the treatment D.Although irrigation is an efficient measure,capable of decreasing water stress,both WUE and WUEet decreased with increasing in irrigation for the three seasons.This shows that higher irrigation decreased WUE and WUEet of crops,which is not consistent with the findings of Hedge (1987),who found that the irrigation significantly increased WUE of crops.GY ranged from 3328to 5583kg ha À1.The GY of treatment C was the highest while GY of treatment E was the lowest corresponding to the small amount of irrigation.There were significant differences between treatment E and other treat-ments at P =0.01.Differences in seasonal rainfall made no difference to the GY of E treatment,possibly because of rainfall distribution.The results of three seasons indicated thattreatment C was better for higher GY,WUEi,and WUE.The results were consistent with those of Yu (1995).3.4.Inter-relationships between GY,IR and ETThe responses of grain yield to the amount of irrigation and ET can be described using a quadratic equation and their relationships were significant at P =ing the equations,the calculated optimal amounts of irrigation for winter wheat at maximum yield were 304,303and 286mm for the three seasons,respectively,and averagely it was 298mm.The calculated optimal levels of ET were 395,427and 457mm for the 3years,respectively,and the average amount was 426mm.The average ET without water deficit for winter wheat was 453mm,reported by Liu et al.(2002)at the same site.The optimal ET for GY being lower than the potential ET indicated that it was not necessary to supply water sufficiently to achieve maximum GY.The relationships between GY and irrigation amounts,ET were related in a second order function for the different winter wheat seasons (Figs.2and 3).All this showed they had similar trends and the GY of winter wheat does not always increase with increasing amounts of irrigation and ET.When the amount of water reached a certain level,the grain yield would decrease.ET was controlled by the meteorological factors and plant factors and they were consistent in the three crop seasons.The reasons for the difference among the amounts of irrigation in the three seasons were soil water storage and rainfall.Thus,an irrigation strategy could be developed according to the rainfall and soil water storage.4.Conclusions and discussionIn this study ET was linearly related to the amount of irrigation.There was about 30mm difference in soil evapora-tion and 25mm difference in leakage among different treatments.Maximal yield was obtained when the optimal amount of irrigation was 298mm and ET was 426mm,averagely for the three seasons However,the seasonal irrigation application should vary with seasonal rainfall and the moisture condition before sowing,since the depletion to soil profile was considerable in the ET components.Excessive irrigation encouraged stem growth and delayeda g r i c u l t u r a l w a t e r m a n a g e m e n t 85(2006)211–218216Fig.2–Relationships between grain yield (GY)of winter wheat and irrigation in 1999/2000,2000/2001and 2001/2002.Fig.3–Relationships between grain yield (GY)andevapotranspiration (ET)in 1999/2000,2000/2001and 2001/2002.the development of winter wheat that decreased GY.In the NCP,the grain-filling period for winter wheat is shorter,lasting about1month from the beginning of May to the10th of June. Dry and hot wind in May and June accelerates the maturity that may reduce harvest index and seed weight.This might be one of the reasons that well-watered winter wheat did not produce the maximum yield.Another important reason is that winter wheat responses differently to water stress at its different growing stages.Zhang et al.(2003)founded that the most sensitive stage of winter wheat to water stress was from stem elongation to booting,followed by anthesis. Irrigation at recoverage reduced GY because it encouraged the growing of non-functional tillers that consumed nutrient reservation.The three seasons’results indicated that treatment C (without irrigation at grainfilling stage)was the best related to WUEi,WUE,and GY.Then irrigation at grain-filling should be withheld.The results showed that with the increase in irrigation ET increased and WUE decreased.Considering the serious water shortage situation in NCP,irrigation might be further reduced to prevent the rapidly falling groundwater level with less sacrifice in grain yield than that in ET. Furthermore,it is also useful to the other irrigated farming regions by the groundwater.Besides the irrigation scheduling to improve WUE of winter wheat,reducing soil evaporation is also an effective method. The results from this experiment showed that E/ET was around30%,considerable water was consumed in soil evaporation.How to improve straw mulching and no-till to winter wheat to reduce soil evaporation was being considered in this region(Huang et al.,2004;Chen et al.,2005).Some researchers reported that the effects of different tillage practices on conserving water(Radcliffe et al.,1988;Unger et al.,1991).Hoeing soil surface was effective to reduce soil evaporation,but it required labor input and it was not popular. Even under optimized irrigation scheduling and water-saving practices,winter wheat still requires large amount of irriga-tion.From a long point of view,reducing winter wheat cropping area might be an option.Yang and Zehnder(2001) proposed to reduce irrigated area to deal with water scarcity in NCP through virtual water import.Policies dealing with water scarcity should be taken into account.AcknowledgmentsProject supported by the National Natural Science Foundation of China(No:40371024);the project of Hebei science and technology department(No:06220112D),China.r e f e r e n c e sAggarwal,P.K.,Singh,A.K.,Chaturvedei,G.S.,Sinha,S.K.,1986.Performance of wheat and triticale cultivars in a variablesoil-water environment.II.Evapotranspiration,water useefficiency,harvest index and grain yield.Field Crops Res.13, 301–315.Bos,M.G.,1985.Summary of ICID definitions of irrigation efficiency.ICID Bull.34,28–31.Chen,S.,Zhang,X.,Pei,D.,Sun,H.,2005.Effects of corn straw mulching on soil temperature and soil evaporation of winter wheatfield.Transact.CSAE21(10),171–173(in Chinese). Daamen,C.C.,Simmonds,L.P.,Wallace,J.S.,Laryea,K.B.,1993.Use micro-lysimeters to measure evaporation from sandy soils.Agric.For.Mete.96,159–173.English,M.,1990.Deficit irrigation.I.Analytical framework.J.Irrig.Drainage ASCE116,99–412.English,M.,Raja,S.N.,1996.Perspectives on deficit irrigation.Agric.Water Manage.32,1–14.Gajri,P.R.,Gill,K.S.,Chaudhary,M.R.,1997.Irrigation of sunflower(Helianthus annuus)in relation to tillage andmulching.Agric.Water Manage.34,149–160.Hagan,R.M.,Howard,R.H.,Talcoh,W.E.,1967.Irrigation of agricultural lands.Am.Soc.Agron.U.S.A.680–681. Hedge,D.M.,1987.The effect of soil water potential method of irrigation,canopy temperature,yield and water use ofradish.Hortic.Sci.62(4),507–511.Hu,C.S.,Zhang,X.Y.,Cheng,Y.S.,Pei,D.,2002.An analysis on dynamics of water table and overdraft in the piedmont of pr.Stud.Agric.18(2),89–91(in Chinese).Huang,Y.,Chen,L.,Fu,B.,Huang,Z.,Gong,J.,2004.The wheat yields and water-use efficiency in the Loess Plateau:straw mulch and irrigation effects.Agric.Water Manage. Hussain,G.,Al-Jaloud,A.A.,Al-Shammary,S.F.,Karimulla,S., 1995.Effect of saline irrigation on the biomass yield and the protein,nitrogen,phosphorus and potassium composition of alfalfa in a pot experiment.J.Pl.Nutr.18,2389–2408. Jin,M.G.,Zhang,R.Q.,Gao,Y.F.,1999.Temporal and spatial soil water management:a case study in the Heiloonggangregion,PR China.Agric.Water Manage.42,173–187. Kang,S.Z.,Zhang,L.,Liang,Y.L.,Hu,X.T.,Cai,H.J.,Gu,B.J.,2002.Effects of limited irrigation on yield and water use efficiency of winter wheat in the Loess Plateau of China.Agric.Water Manage.55,203–216.Li,F.M.,Zhao,S.L.,Duan,S.S.,1995.The strategy for limited irrigation of spring wheat in semiarid Loess Plateau,China.Chin.J.Appl.Ecol.6(3),259–264(in Chinese).Liu,C.,Wei,Z.,1989.Agricultural Hydrology and Water Resources in the North China Plain.Chinese Scientific Press, Beijing,236pp.(in Chinese).Liu,C.M.,Zhang,X.Y.,Zhang,Y.Q.,2002.Determination of daily evaporation and evapotranspiration of winter wheat and maize by large-scale weighing lysimeter and micro-lysimeter.Agric.For.Mete.111,109–120.Ministry of Geology and Mineral Resources,1986.Report on groundwater resources assessment.Beijing,China. Mogenson,V.O.,Jeensen,H.E.,Rab,M.A.,1985.Grain yield,yield components,drought sensitive,and water use efficiency of spring wheat subjected to water stress at various growth stages.Irrig.Sci.6,131–140.Musick,J.T.,Jones,O.R.,Stemart,B.A.,Dusek,D.A.,1994.Water–yield relationships for irrigated and dry land wheat in the US southern plains.Agron.J.86,980–986.Olesen,J.E.,Mortensen,J.V.,Jorgensen,L.N.,Andersen,M.N., 2000.Irrigation strategy,nitrogen application and fungicide control in winter wheat on a sandy soil.I.Yield,yieldcomponents and nitrogen uptake.J.Agric.Sci.134,1–11. Radcliffe,D.E.,Tollner,E.W.,Hargrove,W.L.,Clark,R.L.,Golabi, M.H.,1988.Effect of tillage practices on infiltration and soil strength of a Typic Hapludult soil after10years.Soil Sci.Soc.Am.J.52,798–804.Singh,S.D.,1981.Moisture-sensitive growth stages of dwarf wheat and optimal sequencing of evapotranspirationdeficits.Agron.J.73,387–391.Singh,P.K.,Mishra,A.K.,Imtiyaz,M.,1991.Moisture stress and the water use efficiency of mustard.Agric.Water Manage.20,245–253.a g r i c u l t u r a l w a t e r m a n a g e m e n t85(2006)211–218217。

航空发动机专业英语词汇大全，值得收藏！之袁州冬雪创作2016-01-29 航佳技术飞机维修砖家Part 1Para. 1gas turbine engine燃气涡轮发动机aircraft 飞机，飞行器（单复同形）power plant 发动机，动力装置appreciate 懂得，意思到prior to 在…之前propulsion 推进reaction 反作用jet 喷气, 喷射, 喷气发动机designer 设计师initially 最初，开端时unsuitability 不适应性piston engine 活塞发动机airflow 空气流present 带来, 发生obstacle 障碍Para. 2patent 专利, 获得专利jet propulsionengine 喷气推进发动机athodyd 冲压式喷气发动机heat resistingmaterial 耐热资料develop 研究出，研制出in the secondplace 其次inefficient 效率底的ram jet, ramjet冲压式喷气发动机conception 构想, 设计，概念Para. 3grant 授予propulsive jet 推进喷射turbo-jet engine 涡轮喷气发动机turbojetturbo-propellerengine涡轮螺桨发动机turbopropVickers Viscountaircraft 维克斯子爵式飞机be fitted with 配备term 术语, 称为, 叫做twin-spool engine 双转子发动机triple-spoolengine三转子发动机by-pass engine 双涵道发动机ducted fan 涵道风扇发动机unducted fan (UDF)无涵道风扇发动机propfan 桨扇发动机inevitable 不成防止的, 必定的propeller 螺旋桨basic principle 基来历根基理effect 发生propel 推进solely 单独, 只thrust 推力popularly 普遍地, 一般地pulse jet 脉动式喷气发动机turbo/ram jet 涡轮冲压式喷气发动机turbo-rocket 涡轮火箭accelerate 加速acceleration 加速度apparatus 装置, 机器slipstream 滑流momentum 动量issue 冒出to impart M to N 把M给与Nrevolve 旋转whirl 旋转sprinkler 喷水器mechanism 机构by [in] virtue of 依靠hose 软管afford 提供carnival 狂欢节definitely 确切地, 明白地assume 想象, 以为expel 排出, 驱逐propulsiveefficiency 推进效率Page 3differ 分歧convert 转换thermodynamic 热动力的divergent 分散diverge 分散convergent 收敛converge收敛entry 进气段exit 排气管kinetic energy 动能air intake 空气出口diverging duct 分散管道outlet duct 排气管missile 导弹target vehicle 靶机intermittentcombustion 间断式燃烧aerodynamic 空气动力的involve 具有robust 坚固的, 坚固的inlet valve 进气阀inject 喷入eject 喷出depression 降压, 减压exhaust 排气cycle 循环helicopter rotorpropulsion直升飞机旋翼驱动器dispense with 省去, 无需resonate 共振resonating cycle 共振循环fuel consumption 燃油消耗equal 比得上performance 性能decompose 分解inherent 固有的draw 吸入arrangement 布局simplicity 简单性subsequent 接下来的thermodynamic 热力的Page 7disturbance 扰动blade-tip 叶尖departure from 变节offset 抵消exceed 超出Mach number 马赫数variable intake 可变出口afterburning 加力燃烧variable nozzle 可调喷口conventional 惯例的afterburner 加力燃烧室inoperative 不工作的divert 使转向guide vane 导流叶片duct 管道，用管道输送sustained 持续的cruise 巡航mode 形式multi-stageturbine 多级涡轮derive 得到，取得kerosene, kerosine火油be in the orderof…达到…的量级spray 喷雾fuel-rich mixture 富油混合物dilute 稀释surplus 剩余的interceptor 截击机space-launcher 航天发射器altitude 高度attitude 态度、姿态latitude 纬度longitude 经度accelerative 加速的duration 持续时间Part2working fluid 工作流体conversion 转换jet efflux 喷射气流four-stroke pistonengine 四冲程活塞发动机constant pressure 等压constant volume 等容induction 进气compression 压缩intermittent 间断的be involved in…与…有关charging 进气eliminate 消除idle stroke 空冲程peak 峰, 峰值fluctuate,fluctuating 动摇, 起伏withstand,withstood 承受in excess of 超出employ 采取cylinder 汽缸high octane fuel 高辛烷值燃料low octane fuel 低辛烷值燃料fabricated 装配式的function 运行, 运转introduce,introducing 输入remainder 剩余部分discharge 排出Para.5,6turbine assembly 涡轮部件air-cooled blade 气冷叶片consequently 随之而来的, 因此, 所以embody 体现be embodied in M 体现在M中be directlyproportional to…与…成正比be inversely proportional to…与…成反比trace 描画show up 表示attain 达到, 实现conversely 相反地adiabatic 绝热的friction 磨擦conduction 传导turbulence 紊流propelling nozzle 推力喷管momentum 动量deceleration 减速Page 14effect 实现conversion 转换convert 转换sonic 音速的subsonic 亚音速的supersonic 超音速的encounter 遇到venturi 文氏管interference 干扰component failure 部件失效eddy 涡流turbulence 紊流frontal area 迎面面积straight-throughflow system 直流式系统reverse flowsystem 回流式系统subsequent 接下来的conventionally 惯例地percentage 部分，百分比duct 管道，用管道输送remainder 剩余物deliver 送，流to be conduci ve to…有利于…specific fuelconsumption 燃油消耗率design feature 设计特征by-pass engine 双涵道发动机by-pass ratio 涵道比twin-spoolconfiguration 双转子布局propfan 桨扇发动机turbo-propeller 涡轮螺桨发动机by-pass airstream 外涵道气流overboard 向船外，排出ducted fan 涵道式风扇发动机aft fan 后风扇发动机Part 3centrifugal 离心的axial 轴流的couple 耦合，联接coupling 联轴器coupler联轴器shaft 轴centrifugal (flow)compressor 离心压气机impeller 叶轮diffuser 分散器axial (flow)compressor 轴流压气机multi-stage unit 多级装置alternate 交替的rotor blade转子叶片stator vane 静子叶片diffuse 分散boost 增压booster 增压器with regard to 关于robust 坚固，坚固develop andmanufacture 设计与制造consume 消耗，使用attain 达到air flow 空气流量，空气流adoption 采取favour (Am. E favor) 喜爱，偏爱ruggedness坚固性rugged 坚固的outweigh 胜过，重于Fig. 3-1rotating guidevane 旋转导流叶片intake chute 进气斜道swirl vane 旋流叶片diffuser vane 分散器叶片double-entry impeller双面进气叶轮plenum chamber 稳流室induce 吸入radially 径向地intake duct 进气管initial swirl 预旋divergent nozzle 分散排气管tip speed 叶尖速度maintain 坚持leakage 泄漏clearance 间隙construction 布局center around(about, at, in, on, round, upon)…以…为中心ball bearing 滚珠轴承roller bearing 滚柱轴承split 分开detachment 拆开，分离forged 锻造的radially disposedvanes 径向摆列的叶片in conjunctionwith… 和…共同swept back 后掠attach 联接tangential 相切的inner edge 内缘in line with… 与…一致buffeting impulse 扰流抖振脉冲Para. 13rotor assembly 转子部件airfoilsection 翼型截面mount 装置bearing 轴承incorporate 安有，装有in series 依次地design condition 设计状态incorporation 引入，采取variable statorvane 可调静子叶片succeeding stage下一级Para. 14gradual reduction 逐渐减小annulus 环型stator casing 静子机匣maintain 坚持density 密度convergence 收敛taper，tapering 带斜度，带锥度arrangement 布局Para. 16multi-spoolcompressor 多转子压气机optimum 最佳（的），最优（的）flexibility 适应性，矫捷性Para. 17handle 处理duct 管道，用管道输送exhaust system 排气系统propelling nozzle 推力喷管match 使匹配obsolete 已不必but 除…….之外Para. 18trend 趋势stage 阶段, 级undergo 承受split 分开core 核心gas generator 燃气发生器optimumarrangement 最佳布局Para. 19induce 吸入，引入，引导sweep, swept 扫，猛推adjacent 相邻的translate 翻译，转换decelerate 减速serve 起……作用deflection 偏转straightener 整流器swirl 旋流diagrammatically 图示地accompany 陪同progressive 不竭的，逐渐的Para. 20breakaway 分离stall 失速precede 在……前面Para. 21incidence 攻角tolerate 允许interstagebleed 级间放气intermediatestage 中间级Para. 22proportion 比例 pl. 尺寸, 大小coaxial 同轴的inner radius 内半径supercharge 增压akin 相似的to center around(round, on, upon, about, at, in)…以…为中心alignment 对中, 同心cylindrical 圆筒形的bolted axial joint轴向螺栓联接bolted center linejoint 中心线螺栓联接secure 固定assemble 装配weld 焊接periphery 边沿drum 鼓筒circumferential 周向的fixing 装置, 固定maintainability 维护性blisk 整体叶盘gradient 梯度balance out 抵消twist 扭angle of incidence攻角boundary layer 附面层, 鸿沟层stagnant 滞止的compensate for 抵偿camber 弯度extremity 端部end-bend 端弯retaining ring 坚持环in segments 成组的shroud 叶冠dissimilar 不相似的, 分歧的workable 可用的, 可运转的implement 实现, 执行, 完成retain 坚持impose upon… 强加于…之上depart from 偏离intention 意图positive incidencestall 正攻角失速negative incidencestall 负攻角失速blading 叶栅sustain 承受得住surge 喘振instantaneous 即刻的expel 排出margin 欲度instability 不稳定性Para. 30provision 提供margin 欲度hydraulic 液压的pneumatic 气动的electronic 电子的Para. 31cost effective 成本效益好的prevail 风行，胜利Para. 32rigid 刚性的clearance 间隙alloy 合金nickel based alloy镍基合金titanium 钛in preference to 优先于rigidity todensity ratio 刚度密度比Para. 33prime 主要的fatigue strength 疲劳强度notch 切口，开槽ingestion 吸气inferior 差的decline 下降rub 碰磨ignite 点燃airworthiness 飞行性能hazard 危险Para. 34dominate 起支配作用Para. 35solid forging 实锻件chord 弦mid-span 叶片中部snubber 减振器clapper 点头fabricate 制造skin 蒙皮honeycomb 蜂窝Para. 36robust section 坚固截面ingestioncapability 吸气才能Part4fuel supply nozzle燃油喷嘴extensive 广泛的，大量的accomplish 完成range 范围C---Centigrade orCelsius turbine nozzle涡轮导向器consequent 随之发生的，成果的kerosene, cerosine火油light, lit orlighted 点燃blow, blew，blown 吹alight 燃烧的flame tube 火焰筒liner 衬筒meter, metering 调节配量snout 进气锥体downstream 下游，顺流swirl vane 旋流叶片perforated flare 带孔的喇叭管primary combustionzone 主燃区upstream上游，逆流promote 促进，引起recirculation 环流，回流secondary air hole二股气流孔toroidal vortex 喇叭口形涡流anchor, anchoring 锚，固定hasten 促进，加速droplet 小滴ignitiontemperature 燃点conical 锥形的intersect 相交turbulence 紊流break up, breakingup 分裂，破碎incoming 出去的nozzle guide vane 涡轮导向叶片amount to 占…比例, 达到progressively 逐渐地dilution zone 掺混区remainder 剩余物insulate M from N 使M与N隔离Para.10,11electric spark 电火花igniter plug 点火塞self-sustained 自持的airstream =airflowdistinct =different type injection 喷射，喷入ejection 喷射，喷出atomize 使雾化spray nozzle 喷嘴pre-vaporization 预蒸发vapor 蒸汽vaporize 蒸发vaporizer 蒸发器feed tube 供油管vaporizing tube 蒸发管atomizer flametube装有雾化喷嘴的火焰筒multiple(combustion) chamber 分管燃烧室tubo-annular(combustion) chamber 环管燃烧室cannular(combustion) chamber 环管燃烧室annular(combustion) chamber 环形燃烧室dispose 安插delivery 排气interconnect 互相连通propagate传播bridge a gapbetween填补空缺，使毗连起来evolutionary 发展，演变arrangement 布局overhaul 大修compactness 紧凑性contain 包含，装置be open to 与…相通elimination 消除propagation 传播virtually 实际上oxidize 氧化carbon monoxide 一氧化碳non-toxic 无毒的carbon dioxide 二氧化碳aerate, aerating 吹气，供气over-rich pocket 过富区fuel vapour 燃油蒸汽carbon formation积碳形成incur 招致extinction 熄灭relight 重新点燃perform,performing 完成，执行spray nozzleatomizer 喷嘴雾化器intensity 强度compact 紧凑的exceptionally 格外地，特别地calorific value 热值British thermalunit (BTU)英国热量单位=252卡expenditure 使用，消耗altitude cruise 高空巡航weak limit 贫油极限rich limit 富油极限extinguish 熄灭extinguisher 灭火器dive 俯冲idle, idling 空载，慢速mixture strength 混合物浓度stability loop 稳定区emission 排放物pollutant污染物create 发生，形成legislatively 立法地hydrocarbon 碳氢化合物oxides of nitrogen氧化氮suppression 抑制desirable 合乎需要的conflict 冲突compromise 折中combustor 燃烧室substantially 实际上coating 涂层insulation 隔热，隔离corrosion 腐蚀creep failure 蠕变失效fatigue 疲劳Part5accessory,accessories 附件solely = onlyextract,extracting 提取to expose M to N 使M吐露于NM is exposed to Ntorque 扭矩intermediate 中间的interpose 置于…之间to be derivedfrom… 从…获得, 取自free-power turbine自由动力涡轮to be independentof…不受…的限制mean 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惯例的impractical 不实际的dual alloy disc 双金属轮盘blisk 整体叶轮cast 铸造bond 粘接match 匹配nozzle guide vane 涡轮导向叶片back pressure 反压surge 喘振choke 壅塞，阻塞obstacle 障碍impart to…给与tensile stress 拉应力limiting factor 限制因素endure 承受nickel alloy 镍合金ceramic coating 陶瓷涂层enhance 增强resistance 抵抗，耐fatigue cracking 疲劳破坏ferritic 铁素体terrific 恐怖的，极妙的austenitic 奥氏体alloying element 合金元素extend 延长fatigue resistance抗疲劳性powder metallurgy 粉末冶金in connection with关于，与…有关glowing red-hot 赤热发光ounce 盎施=28.35 gbending load 弯曲载荷thermal shock 热冲击corrosion 腐蚀oxidization 氧化foregoing 前面的, 上述的it follows that 因此, 可见permissible 允许的metallurgist 冶金学家creep 蠕变finite useful life有限使用寿命failure 失效forge 锻造forging 锻件cast 铸造creep property 蠕变性能fatigue property 疲劳性能reveal 揭露, 显示a myriad of 无数crystal 晶体equi-axed 等轴的service life 使用寿命directionalsolidification 定向凝结useful creep life 有效蠕变寿命single crystalblade 单晶叶片substantially 实质上, 显著地reinforced ceramic加固陶瓷balancing 平衡operation 工序in view of 思索到Part 6aero 航空的pass 排送resultant thrust 合成推力，总推力create 引起，发生contribute 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[转载]垂直坐标系原⽂地址：垂直坐标系作者：泗⽔渔隐/class/metr452/models/2001/vertres.htmlVertical Resolution and CoordinatesIntroductionProperly depicting the vertical structure of the atmosphere leads to better forecasts by Numerical Weather Prediction Models. To successfully understand this vertical structure, the model must have an appropriate vertical coordinate to lead to better resolution and thus better forecasts. Numerical Weather Prediction models produce these forecasts by computing the average over these coordinate surfaces, rather than on the surface itself. At this point, one familiar with forecasting models might ask: "Why not use pressure and height surfaces, as they are used in most maps anyway?" The reason that these surfaces are not used in Numerical Weather Prediction is because they cause much confusion at the ground. Therefore, other surfaces have been developed and used in the vertical. Some of the most popular surfaces used in many of the current models are the Sigma, Eta, and Theta surfaces(UCAR, 2000). These will be the surfaces we will focus our attention to in this webpage, describing each vertical coordinate system, giving examples of models from coordinate systems, and making an evaluation of the coordinate types.Description of Vertical Coordinate SystemsSigma CoordinateThe sigma coordinate system defines the base at the model's ground level. The surfaces in the sigma coordinate system follow the model terrain and are steeply sloped in the regions where terrain itself is steeply sloped. the sigma coordinate system defines the vertical position of a point in the atmosphere as a ratio of the pressure difference between that point and the top of the domain to that of the pressure difference between a fundamental base below the point and the top of the domain.Because it is pressure based and normalized, it is easy to mathematically cast governing equations of the atmosphere into a relatively simple form.Advantges1) The sigma coordinate system conforms to natural terrain. This allows for good depiction of continous fields, such as temperature advection and winds, in areaswhere terrain varies widely but smoothly.2) It lends itself to increasing vertical resolution near the ground. This allows the model to better define boundary-layer processes, such as diurnal heating, low-level winds, turbulence, low-level moisture, and static stability.3) Eliminates the problem of vertical coordinate systems intersecting the ground, unlike height or isentropic coordinates.Limitations1) The model wind forecast depend upon accurate calculations of the pressure gradient force (PGF). This is easly calculated in pressure coordinates when theheight is known. Yet, when sigma surfaces slope, the PGF must be expanded to include the effects of the slope. This introduces errors because the lapse ratemust be approximated at points that lie in between the pressure surfaces where height is observed.2) Sigma models have a difficult time dealing with weather events on the lee-side of mountain ranges (i.e. cold-air damming, lee-side cyclogenesis).3) Because of the smoothing required in the mountain ranges along coastlines, land points can be forced to extend beyond the true coastline.Examples of Sigma Models or VarientsAviation/Medium Range Forecast (AVN/MRF) ModelIt has a vertical domain that runs from the surface to about 2.0 hPa. For a surface pressure of 1000 hPa, the lowest level is at about 996 hPa.The vertical domain is represented by a sigma coordinate and a Lorenz grid.It uses a quadratic conserving finite difference scheme.The resolution is divided into 42 unequally spaced sigma levels, where for a surface pressure of 1000 hPa, twelve levels are below 800 hPa, twenty levelsbetween 800hpa and 100hpa, and ten are above 100 hPa. (COMET)As of 9 January, 2001, The GSM had the following settings (GMBOB):Spectral triangular 170 (T170) Horizontal Resolution.The Gaussian grid of 512x256, roughly equivalent to 0.7x0.7 degree latitude/longitude.A Vertical Representation in Sigma coordinates on a Lorenz grid with a Quadratic conserving finite difference scheme by Arakawa and Minz (1974).Nested Grid Model (NGM):The terrain following system simplifies the treatment of processes at the bottom of the model atmosphere.The same vertical structure of 16 layers is carried throughout the analysis, initialization, and forecast components of the NGM to eliminate inconsistenciesthat may arise through vertical interpolation.The thickness of the layers in the NGM change smoothly with height, with greatest resolution near the bottom of the atmosphere, with the bottom layer being35 millibars thick when the surface pressure is 1000 millibars, and 17.5 millibars thick when the surface pressure is 500 millibars.The pressure thickness of the layers increase with height to a maximum in layer-10 (near 450 mb) of 75 mb when the surface is 1000 mb.The high resolution near the surface in the NGM is desirable for capturing the behavior of boundary layer processes in the NGM analysis and forecast(Hoke,James E. ; 325).European Center Medium Range Weather Forecasting Model (ECMWF):The European Center for Medium-range Weather Forecasting model uses 31 levels between the earth's surface and 30 km.With a horizontal resolution of 60 km, the model forecasts at 4,154,868ATMO689/Lecture8/ points in the upper air.With this resolution, it can produce forecasts for near surface weather parameters such as local winds and temperature (Woods 1998).Example of Sigma Coordinate ModelETA Coordinate ModelThe fundamental base in the eta system is not at the ground surface, but instead is at mean sea level. The eta coordinate system has surfaces that remain relatively horizontal at all times. At the same time, it retains the mathematical advantages of the pressure based system that does not intersect the ground. It does this by allowing the bottom atmospheric layer to be represented within each grid box as a flat "step". The eta coordinate system defines the vertical position of a point in the atmosphere as a ratio of the pressure difference between that point and the top of the domain to that of the pressure difference between a fundamental base below the point and the top of the domain. The ETA coordinate system varys from one at the base to zero at the top of the domain. Because it is pressure based and normalized, it is easy to mathematically cast governing equations of the atmosphere into a relatively simple form.Advantges1) Eta models do not need to perform the vertical interpolations that are necessary to calculate the PGF in sigma models (Mesinger and Janji 1985). This reducesthe error in PGF calculation and improves the forecast of wind and temperature and moisture changes in areas of steeply sloping terrain.2) Although the numerical formulation near the surface is more complex, the low-level convergence in areas of steep terrain are far more representative of realatmospheric conditions than in the simpler formulations in sigma models (Black 1994). The improved forecasts of low-level convergence result in betterprecipitation forecasts in these areas. The improved predictable flow detail compared to a comparable sigma model more than compensates for the slightlyincreased computer run time.3) Compared with sigma models, eta models can often improve forecasts of cold air outbreaks, damming events, and leeside cyclogenesis For example, in cold-airdamming events, the inversion in the real atmosphere above the cold air mass on the east side of a mountain are preserved almost exactly in an eta model.Limitations1) The step nature of the eta coordinate makes it difficult to retain detailed vertical structure in the boundary layer over the entire model domain, particularly overelevated terrain.2) Eta models do not accurately depict gradually sloping terrain. Since all terrain is represented in discrete steps, gradual slopes that extend over large distancescan be concentrated within as few as one step. This unrealistic compression of the slope into a small area can be compensated, in part, by increasing the vertical and/or horizontal resolution.3) Eta models have difficulty predicting extreme downslope wind events.An example of ETA Step ModelsETA ModelThis model uses 50 vertical levels (NCEP 2000).The eta coordinate was used in order to remove the large errors which are known to occur when computing the horizontal pressure gradient force, as well asthe advection and horizontal diffusion along a steeply sloped coordinate surface, such as the sigma surfaces in the NGM model (Mesinger, 1984).This coordinate system makes the eta surfaces quasi-horizontal everywhere as opposed to sigma surfaces which can be steeply sloped(Black, 1994).This model is often being updated, and changes are made quite frequently on its resolution.Example of Cold-Air DammingTheta Coordinate Model SystemAdvantges1) Potential vorticity is better conserved, and precipitation spin-up in short-range forecasts is reduced.2) 3-D advection becomes essentially 2-D in theta coordinates.3) The theta coordinate allows for more vertical resolution in the vicinity of baroclinic regions like fronts and near the tropopause, this allows more accuratedepictions of significant horizontal and vertical wind shears and het streaks.4) Vertical motion through isentropic surfaces is caused almost exclusively by diabatic heating. Vertical motion isentropic models is a result of two processes:adiabatic motion and diabatic forcing. Adiabatic vertical motions are included within the horizontal component of the isentropic forecast equations. By having the total vertical motion related only to these adiabatic components, there is afar more direct cause and effect relationship in interpreting the mdel forecast fields.5) Isentropic coordinate models conserve important dynamical quantities such as ptential vorticity.Limitations1) A MAJOR limitation of the theta coordinate system occurs in the boundary layer, where the flow can be strongly non-adiabatic.2) Isentropic surfaces intersect the ground so they cannot be located at all times during the day. That's why sigma coordinates are used in the boundary layer. Thisallows at least five layers of the model to follow surface terrain.3) Isentropic coordinates may not exhibit monotonic behavior with height in the boundary layer. If superadiabatic layers develop in the boundary layer due todiurnal heating, isentropic surfaces then appear more than once in the vertical, about a point. This can't be allowed in the models vertical coordinate system, and could severely limit the model's ability to predict many weather advents.4) Vertical resolution in nearby adiabatic layer is coarse. The same quality that leads to enhanced resolutions in baroclinic zones conversely means that largeadiabatic regions will have decreased vertical resolutions when theta coordinates are used. This leads to problems in adequately resolving the vertical mixing in these regions.Explenation of Theta SystemSince the flow in the free atmosphere is mostly isentropic, potential temperature is useful as a vertical coordinate system. Since non-adiabatic processesdomintate in the boundary layer and potential temperature intersects the earth's surface, theta coordinates are not used alone in any of the models. Instead they do work very well as a hydrid system, since they handle motions about the boundary layer very-well.The RUC-2 model uses a hybrid system. Theta coordinates are used aloft in the RUC-2 model. It provides improved resolution where there are large temperatures gradients. Much of the interesting weather takes place in this area. RUC-2 is used for short-range weather forecasting or "now casting".Example of Isentropic ModelHybrid Coordinate ModelsThe hybrid coordinate sytem is a combination of both a theta coordinate system (above the boundary layer) and a sgima coordinate system (below the boundary layer).Theta coordinates are isentropic coordinates that are layered throughout the atmosphere. The theta surfaces are not used near the ground due to the fact that they are not terrain following coordinates. Instead, the sigma coordinates are used near the surface of the earth.Advantges1) This system retains the advantages of isentropic models in the free atmosphere, including better precipitation starting times for isentropic upglide than in sigma-coordinate models.2) This system eliminates the problem of isentropic surfaces intersecting the ground.3) This system represents surface heating and dynamical mixing in the boundary layer well.4) The system allows good surface physics interactions, including surface evaporation and treatment of snow cover.Limitations1) Hybrid isentopic-sigma models no longer preserve adiabatic flow in the boundary layer as easily as pure isentropic models.2) The depth of the sigma layers does not match the true depth of the PBL, so processes near the PBL/free atmosphere interface may not be depicted with the bestcoordinate.3) It can be difficult to blend coordinate types at their interfaces.An Example of the Hybride Coordinate SystemRapid Update Cycle (RUC-2)The RUC-2 has 40 vertical levels.The minimum potential temperature spacing occurs through much of the tropopause and is 2K.The top level is 450K.It continues to use a generalized vertical coordinate configured as a hybrid isentropic-sigma coordinate in both the analysis and model.This coordinate has proven to be very advantageous in providing sharper resolution near fronts and the tropopause. (e.g., Benjamin 1989, Johnson et al.1993, Zapotocny et al. 1994).The prespecified pressure spacing in RUC-2, starting from the ground is 2, 5, 8, and 10 mb, followed by as many 15-mb layers as are needed. This terrain-following spacing compacts somewhat as the terrain elevation increases. This provides excellent resolution of the boundary layer in all locations, includingover higher terrain.The RUC-2 has an explicit level actually at the surface; no extrapolation from higher levels is necessary to diagnose values at the surface.Figure 4: Hybrid Coordinate System(See Description Below)[The above picture is a sample cross section of RUC-2 native levels. This is the same picture used above as an example of a hybrid coordinate system. The cross-section is across the United States, passing south of San Francisco California, through Boulder Colorado (where a downslope windstorm occurred that morning) and then through southern Virginia to the East Coast. The cross section is for a 12-h forecast valid at 1200 UTC 30 November 1995.The typical RUC-2 resolution near fronts is apparent in this figure,ATMO689/Lecture8/ as well as the tendency for more terrain-following levels to "pile up" in warmer regions (the eastern part of the cross section, in this case).]Critical Evaluation of Coordinate TypesA) Sigma and Eta Coordinates1) The sigma and eta coordinates are better for uses near the ground since they are terrain-following coordinates compared to the theta coordinate, which is not.2) The sigma and eta coordinates have mathematical advantages of casting the governing equations of the atmosphere into a relatively simple form.3) Both the sigma and eta coordinates also guarantee a certain vertical resolution even when the stratification is weak.4) All of the adiabatic component of the vertical motion on the isentropic surfaces is captured in flow along the 2-D surfaces. Vertical advection, which usually has somewhat more truncation error than horizontal advection, does much less "work" in isentropic/sigma hybrid models than in quasi-horizontal coordinate models. This characteristic results in improved moisture transport and very little precipitation spin-up problem in the first few hours of the forecast.5) Both of these coordinate systems tend to be better for long range forecasting for large areas.B) Theta Coordinates1) Theta coordinates make better use of observations in objective analysis. The influence of the observations is extended along quasi-material theta surfaces along which advection occurs rather than the quasi-horizontal surfaces used with other vertical coordinates.ATMO689/Lecture8/2) Improved quality control: Observations tend to appear more homogeneous on isentropic surfaces than the quasi-horizontal surfaces.3) Vertical truncation error is virtually absent. 3-D advection becomes essentially 2-D in theta coordinates.4) Potential vorticity is better conserved, and precipitation spin-up in short-range forecasts is reduced.5) These are better at looking at short range forecasts as they show large amounts of detail (Nielson-Gammon, 2000).VerticalCoordinateModels Primary Advantage Primary LimitationEta ()Eta Allows for large local differences in terrain from one gridpoint to anotherMay not represent the boundary layer with sufficientresolution over elevated terrainGeneric hybrid ECMWF, NOGAPS Combines strengths of several coordinate systems Difficult to properly interface across coordinate domainsIsentropic-sigmahybrid ()RUCNaturally increases resolution in baroclinic regions, suchas fronts and tropopauseIncompletely depicts important low-level adiabatic flowSigma ()AVN/MRF, NGM,MM5, RAMSSurfaces are terrain-following and therefore resolve theboundary layer wellMay not correctly portray weather events in lee of mountainsThe following table summarizes how well each coordinate meets the criteria for serving as a vertical coordinate.Criteria Sigma Eta Isentropic Hybrid Isentropic-Sigma Exhibits monotonic behavior Yes Yes May not YesPreserves conservative atmospheric properties and processes Fairly well Fairly well Very well WellAccurately portrays pressure gradient force No Yes Mostly MostlyREFERENCES:Benjamin, Stanley G., 1998: RUC-2 - The Rapid Update Cycle Version 2 Technical Procedures Bulletin - Draft. NOAA/ERL Forecast Systems Laboratory, Boulder, CO Black, T.L., 1994: The new NMC mesoscale ETA model: Description and forecast examples. Weather. Forecasting, 9, 265-278.COMET, 1999. AVN/MRF. T170/L42 Vertical Resolution.GMBOB (Global Modeling Branch/Operations Branch), NMC. :8080/research/mrf.html. GSM Model status update.Hoke, James E. et al, 19 Dec. 1988: The Regional Analysis and Forecast System of the National Meteorological Center. NMC, NWS, and NOAA.Kalnay and Kanamitsu, 25 Oct. 1995: Model Status as of Oct. 25, 1995. NMC Development Division.Mesinger, 1984: A blocking technique for representation of mountains in atmospheric models. Riv. Meteor. Aeronaut., 44, 195-202.Nielson-Gammon, John. Lecture on Numerical Weather Prediction, Feb. 9 2000.Nielson-Gammon, John. 1998. The Eta Model: A Tutorial on Numerical Weather Prediction Models.University Corporation for Atmopsheric Research, 2000 /nwp/9cu1/ic2/frameset.htm?opentopic(2) Vertical Coordinates.Staudenmaier, M. Jr., 1996: A description of the MESO ETA model. Western Region [NWS] Technical Attachment NO. 96-06.Environmetal Modeling Center: Log Of Operational ETA Model Changes September 2000. /mmb/research/eta.log.htmlWoods, Austin, 1998: ECMWF-Forecasting by Computer. http://www.ecmwf.int/research/fc by_computer.html: European Centre for Medium-Range Weather Forecasts(ECMWF).Nielson-Gammon, John. Interview on Numerical Weather Prediction, 21 Feb. 2001.Zhang, Fuqing. 2002 NWP Model Notes.Page Last Updated 20 February 2002Updated by:Chris AllenDavid KramerRobert SmithAaron Stults。

浸没边界方法的研究现状概述作者：周兵来源：《科技信息·下旬刊》2017年第02期对流动边界的处理方法是CFD研究的一个关键问题，对复杂边界条件的处理能力直接影响CFD在实际流动计算中的应用。

边界处理与计算网格联系紧密，通常可按计算网格和边界形状的关系分为两类：一类计算网格与边界形状相适应，另一类计算网格和边界则相对独立。

前一类中包括采用贴体网格和非结构网格。

贴体网格中需要对控制方程进行变换，会给计算带来额外负担，同时网格的正交性对解的收敛和精确性有较大的影响。

而非结构网格则需要较大的存储容量并且计算效率比较低。

浸没边界方法是近年来逐渐受到重视和应用的一种计算网格相对独立的边界处理方法，以下就浸没变边界方法的提出以及发展情况进行概要的描述。

1 浸没边界方法浸没边界方法是由Peskin[1] 最早提出的，其基本思想是将边界条件的影响通过在N-S方程中加入一个强迫力f来实现，强迫力只加在边界附近的节点上，流场的内部节点的数值离散保持不变，加强迫力的大涡模拟控制方程可以表示如下：（1）1.1 强迫力的施加方法强迫力的加入主要有两种方案：即反馈强迫力法（Feedback force）和直接强迫力法（Direct force）。

（1）反馈强迫力方法反馈强迫力方法由Goldstein[2]等首先提出，在该方法中，通过在N-S方程中加入负反馈力使得近壁区的节点速度满足给定关系，其实施方法为：（2）其中，，是系数，一般取非常大的负值；而是给定边界处的速度值。

该方法中由于存在与流动有关的参数，对于不同的问题，需要对参数进行调整。

而负反馈力的加入，增大了求解方程的刚性，为使计算稳定，时间步长需要取得非常小。

因此其计算效率比较低。

（2）直接强迫力方法直接强迫力方法由Mohd-Yusof[3]提出，其方程可以表示为：（3）式中力f可以使边界面上的速度u等于给定数值，上式可以写为：（4）如果已知H、、，力就可以简单表达如下：（5）可以看到，f的加入，实际上使得等于，因此在边界处满足给定的速度大小。

国内外流体力学研究机构2008-05-08 09:08:34|分类：C FD |标签：|字号大中小订阅1.北京航空航天大学流体力学研究所http://www.bu /dept5/stress.htm包括国家计算流体力学重点实验室（由李椿萱院士和张函信院士主持）和流体力学开放实验室2. 美国布朗大学流体机械研究中心http://www.cfm.b 了解流体机械的诸多方面3.美国ssesco公司CFD技术服务中心/files/cfd_main.html美国一个著名的计算流体服务机构，解决C FD计算和工程问题的专家4.英国Cra nfield大学CFD研究中心http://www.cra /sme/cfd/主要介绍C FD的在各个领域的应用。

5.欧洲流体湍流及燃烧研究协会（Europe an Research C ommunity On Flow, Turbulence And Combustion ）http://lmfwww.epfl.ch/lmf/ERC OFTAC/领导管理欧洲的流体，湍流及燃烧方面的科研教育和工业的联合组织。

6.美国国家航空和宇宙航行局http://www.nasa.go v/NASA的各项动态和进展，信息很多。

7. 加拿大计算流体力学学会(The CFD Society of Can ada )http://www.cfdsc.ca/english/index.html介绍计算流体力学的进展和应用8. CFD免费软件下载中心(CFD codes list - free softwa re)http://www.cfdsc.ca/english/index.htmlCFD免费软件下载(ft p)9. 美国普林斯顿大学空气动力学实验室(the Princeton Gas Dyn amics Lab )http://www.p /~gasd yn/index.ht ml进行流体力学的前沿研究10. 澳大利亚Monash 大学湍流研究所(The Turbulence Research Laborato ry at Monash Uni versity ).au/~julio/TRL/进行湍流的理论和实验研究及应用11. 美国Syracuse 大学超音速中心(S yracuse University cente r for h ype rsonics)http://www.ma /~h ysonics/介绍超音速材料,实验测量及超音速的CFD计算12. 美国流体动力学研究中心(The Fluid D ynamics Research Center (FDRC) )/流体力学研究中心13. 美国Cornell 大学流体力学研究实验中心（Cha rles Williamson教授领导）(The Fluid D ynamics Research laboratories of Professor Charles Williamson atCornell University)http://vo rtex.m /主要研究涡,湍流和分离流动及其应用14. 荷兰Eindhoven科技大学流体力学实验室(fluid dyna mics laborary of Eindho ven Uni versity of Technology)http://www.fluid.tue.nl/流体力学和热传导的科研和教育机构,主要研究涡,湍流及空气动力学15. 美国FL OMETRICS公司(FL OMETRICS)http://www.flomet /研究流体力学,热力学,自动控制和测量设备的工业公司研究领域包括CFD,实验,理论及流体机械设备16.瑞士机械及机械处理工程能源系统试验室(ETH Zent rum, Mechanical and Process Engineering, Energy S ystems Laborato ry )http://www.les.iet.ethz.ch/内容：研究建筑物内的空气流动，燃烧，能源和环境问题。

２力学与实践２００２年第２４卷１湍流是有结构的不规则多尺度流动打开湍流的名著（如ＴｅｎｎｅｋｅｓａｎｄＬｕｍｌｅｙ［“，ＭｏｎｉｎａｎｄＹａｇｌｏｍ［“，Ｈｉｎｚｃｌ３』等），对于湍流的定义有各种描述，以至丁Ｈｉｎｚｅ说无法给湍流一个公认的定义．这种说法表明，人们对丁湍流的认识在深化中．撇开流体运动的一般特性，比如，流体运动是非线性耗散系统，真实流体运动是有旋流动等．湍流运动的最主要特征是不规则性，这是大家公认的．对于湍流不规则性的深入认识，是ｌＯＯ多年来湍流研究的上要成就之·．早期的科学家认为，像分子运动一样，湍流是完全不规则运动．类似丁分子运动产生黏性，湍流的耗散可以用涡黏系数来表述．２０世纪初，一些杰出的流体力学家，相继对涡黏系数提出各种流体力学的模型，如Ｔａｙｌｏｒ［４１（１９２１年）的涡模型，Ｐｒａｕｄｔｌ［５】（１９２５年）的混合长模型和ｖｏｎＫａｒｍａｎ州１９３０年）相似模型等．当科学家用流体力学观念（不是分子观念）来建市湍流耗散的涡黏模型时，就开始考虑连续介质不规则运动的特点，其中有别于气体分子不规则运动的最主要特点是运动的多尺度性．第一个提出流体湍流运动中多尺度输运特性的科学家ｍｃｈａｒｄｓｏｎ【７】（１９２２年）曾描述湍动能的多尺度传输过程如下：“大涡包含小涡，并喂予速度；小涡包含更小的涡，如此继续直到黏性耗散＇１２）．多尺度的思想导致产生描述多尺度的谱概念和谱分析方法，并最终产生了Ｋｏｌｍｏｇｏｒｏｖ（１９４１年）的局部各向同性的通用谱（即一５／３谱）∽湍流不仅是多尺度的而且是有结构的运动．２０世纪巾叶，大量的湍流实验（包括测量和显示）发现多尺度的湍流运动存在某种特殊的运动状态．ＴｏｗｎｓｅｎｄＩ“（１９５１年），Ｃｏｒｒｓｉｎ［”Ｊ（１９５５年）和Ｌｕｍｌｅｙ［“１（１９６５年）等从脉动序列的间歇性和空间相关相继推测湍流结构的可能形态．理论上也提出过各种湍涡的模型：球涡模型，柱涡模型等．早期的湍流结构主要是从运动学上考虑，把旋涡结构作为湍流统计的样奉．我日司的周培源教授是近代湍流模式的奠基人之一．他白先提｝｝｛先解方程后平均的统计方法，就是说湍涡必须满足Ｎａｖｉｅｒ—Ｓｔｏｋｅｓ方程（ＣｈｏｕａｎｄＣｈｏｕ，１９９５年）＿ｌ…．真实的、可以观察到的湍流结构通过流动显示，以及稍后湍流直接数值模拟所证实．典型的例子是混合层的Ｂｒｏｗｎ—Ｒｏｓｈｋｏ涡（１９７６年）【１３ｌ，图ｌ明显地展示了混合层中存在规则的大涡和分布在大涡周围的细小湍涡．圈１混合层的Ｂｒｏｗｎ—Ｒｏｓｈｋｏ涡（１９７６年）【１２ｌ在边界层、槽道和圆管湍流中也存在各式各样的大涡结构．例如，用激光诱导荧光的显示疗法，我们可以在圆管湍流中观察到周向（图２（ａ））和流向大涡（图２（ｂ））值得提出的是，不仅在剪切湍流中有大涡结构，简单的均匀各向同性湍流中也存在涡结构．图３展示的是各向同性湍流的直接数值模拟中强涡量等值面，它们是管状结构．仔细分析还可以２）原文是：Ｂｉｇｗｈｉｒｌｓｈａｖｅｌｉｔｔｌｅｗｈｉｒｌｓ，ｗｈｉｃｈｆｅｅｄｔｈｅｉｒｖｅｌｏｃｉｔｙ，Ｌｉｔｔｌｅｗｈｉｒｌｓｈａｖｅｓｍａｌｌｗｈｉｒｌｓ，ａｎｄｔｏｖｉｓｃｏｓｉｔｙ第１期张兆顺等：走近湍流ａ）通过圆管轴线的纵截面（ｂ）垂赢轴线的横截面图２圆管湍流的显示（崔桂香，张兆顺，２０００）１１刮确定管状涡的平均长度约等于各向同性湍流的积分尺度，它们的平均直径约等于湍流ＴａｙＬｏｒ微尺度，更进一步分析可以算出管状涡内部的平均速度场，它们接近于Ｂｕｒｇｅｒｓ涡，即有轴向拉伸的柱状涡，在管状涡之间错综复杂地分布着各种尺度的树叉结构．所有以上发现充分说明：无论是简单还是复杂湍流，都存在一定的涡结构．大尺度结构图３菩向同性湍流中的涡站构㈦的发生是不规则的，就是说，在长时间和大范围来观察，大尺度运动结构发生的地点和时划是不确定的．因此在大样本统计中我们不可能发现这种结构，这就是为什么经典的长时间统计未能察觉它们的原因．另一方面，大尺度运动结构一旦生成，它以一定的动力学规律演化，凶此湍流太尺度结构又称拟序结构，或相干结构．举例来说，存湍流边界层、槽道或圆管湍流的近壁区（５＜Ｙ＋＜１００），间歇地发生猝发过程，它们是如下的拟序运动：有一股高速流动冲向壁面（称为下扫过程），它导致近壁区（Ｙ＋一１０）产生流向涡（长度和直径比很大的涡管）；流向涡生成的初期，它缓缓升起，形成和壁面有一定倾角的管状涡（称为上抛过程）；当升至Ｙ＋一３０—５０时，流向涡发生剧烈抖动直至破碎，在流向涡破碎的很短时间内，瞬时的脉动动量通量（一“’”’）很大，可以达到、Ｆ均脉动动量通量，即雷诺应力一（“７”’）的１００倍以上．以上从流向涡的出现到破碎的全过程称为猝发，只要在近壁区触发流向涡，它就以“下扫一卜－抛一抖动一破碎”的序列演化，这就是大尺度运动的拟序性或相干性．湍流中大涡拟序结构对于湍流生成和发展有主宰作用，因此抑制或消除夫涡结构町能抑制整体的湍流强度，甚至使流动层流化．这是近代湍流减阻和降噪的主要思想（Ｂｕｓｈｎｅｌｌ等，１９８９）－ｌ…湍流是多尺度有结构的不规则流体运动．它指出湍流运动的主要特，疰，同时也指出了研究湍流的困难所在．单纯的不规则运动，例如气体分子运动，是不规则粒子群的运动，比较容易用统计力学的方法来分析，囚为宏观上它只有一个特征尺度一分子平均自由程．湍流的第‘个困难是它的多尺度（理论上是无穷多尺度）如果无穷多尺度之间存在简单的关系，例如相似关系，这种多尺度系统也不难处理，但是湍流的多尺度不规则运动是有结构的，也就是说，不同尺度的运动之间的动力学关系足复杂的．本文中，我们将循着“湍流是多尺度有结构的不规则流体运动”这条主线来探讨如何进一步认识湍流．２湍流的直接数值模拟和实验是认识湍流的有２Ｔ具湍流的不规则有结构多尺度运动属于宏观流体运动，即使是最小的湍流耗散尺度也远远大１：分子运动的平均自由程，因此湍流运动，不论它是多么不规则，仍然服从流体运动方程，对于不６力学与实践２００２午第２４卷ｏ（ａ）显示图像的二维脉动速度场（ｈ）图（ａ）右上角的放大圈７粒子图像显示和定量测量ａ）ＬＩＦ显示的图像（ｂ）显示图像的脉动速度场图８ＬＩＦ显不图像和相应的脉动建度场示图像的分析，我们发现，下游的染色带有较大曲率的卷起结构是个强涡，例如图８（ａ）中Ａ；面下游染色带比较平直的卷起结构，只有很微弱的涡量．以上实例说明，流动显示能够给｝｝｛流场的直观图像．然而，没有定量的测量为依据，单凭直觉会引起误导．２０世纪９０年代发展起来的粒子图像测速技术可以和流动显示配合，获得既直观又可靠的湍流场信息．湍流实验面临的困难也是由湍流的多尺度和有结构性质造成的．为了获得湍流脉动场的演化，我们需要脉动场的时间序列，既要达到窄间的分辨率，又要有足够高的采样频率，这在目前还做不到．除了光电器件昂贵以外，高速、高分辨的摄像系统还满足不了湍流研究的要求．总之，湍流直接数值模拟和湍流脉动场的测量足认识湍流多尺度有结构性质的非常有效的工具．由于技术的原因，同前它们只能研究低雷诺数湍流，随着高新技术的发展，愈来愈复杂和精细的湍流现象将被揭示．就直接数值模拟和实验两种方法比较，直接数值模拟在获得信息量度精度、后处理，以及费用来说，它优于物理实验；但是，目前直接数值模拟只能计算简单儿何边界的流动．我们的经验是，对于较低雷诺数的简单湍流，直接数值模拟可以取代物理实验；中等雷诺数以上的复杂边界湍流，物理实验是研究湍流的主要手段．３什么是“最好的”湍流模式湍流模式是封闭湍流统计方程的方法，是目前顶测工程和自然界湍流的唯实用方法．只要预测湍流，就离不开湍流模式．从晟早的Ｂｏｕｓｓｉｎｅｓｑ涡黏模式开始到近代的亚格子应力模式，著走近湍流作者：张兆顺， 崔桂香， 许春晓作者单位：清华大学工程力学系湍流实验室,北京,100084刊名：力学与实践英文刊名：MECHANICS IN ENGINEERING年，卷(期)：2002,24(1)被引用次数：16次1.Townsend AA On the fine-scale structure of turbulence 19512.Kolmogorov AN The local structure of turbulence in incompressible viscous fluid for very large Reynolds number 1941(30)3.崔桂香;张兆顺圆管湍流的近壁涡结构 20004.Brown FNM;Roshko A On density effects and large structure in turbulent mixing layer[外文期刊] 19745.Richardson LF Weather Prediction by Numerical Process 19226.von Kármán T Mechanische Anlichkeit und Turbulenz 19307.Prandtl L Bericht uber Untersuchungen zur ausgebildeten Turbulenz 1925(05)8.Taylor GI Diffussion by continuous movements 19219.Hinze O查看详情 197610.Monin AS;Yaglom AM Statistical Fluid Mechanics: Mechanics of Turbulence (English translation).Vo1. 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风力发电机用专业英语中文对照风力发电机wind turbine风电场wind power station wind farm风力发电机组wind turbine generator system WTGS 水平轴风力发电机horizontal axis wind turbine垂直轴风力发电机vertical axis wind turbine轮毂（风力发电机）hub (for wind turbine)机舱nacelle支撑结构support structure for wind turbine关机shutdown for wind turbine正常关机normal shutdown for wind turbine紧急关机emergency shutdown for wind turbine空转idling锁定blocking停机parking静止standstill制动器brake停机制动parking brake风轮转速rotor speed控制系统control system保护系统protection system偏航yawing设计和安全参数design situation设计工况design situation载荷状况load case外部条件external conditions设计极限design limits极限状态limit state使用极限状态serviceability limit states极限限制状态ultimate limit state最大极限状态ultimate limit state安全寿命safe life严重故障catastrophic failure潜伏故障latent fault dormant failure风特性wind characteristic风速wind speed风矢量wind velocity旋转采样风矢量rotationally sampled wind velocity 额定风速rated wind speed切入风速cut-in speed切出风速cut-out speed年平均annual average年平均风速annual average wind speed平均风速mean wind speed极端风速extreme wind speed安全风速survival wind speed参考风速reference wind speed风速分布wind speed distribution瑞利分布RayLeigh distribution威布尔分布Weibull distribution风切变wind shear风廓线风切变律wind profile wind shear law风切变指数wind shear exponent对数风切变律logarithmic wind shear law风切变幂律power law for wind shear下风向down wind上风向up wind阵风gust粗糙长度roughness length湍流强度turbulence intensity湍流尺度参数turbulence scale parameter湍流惯性负区inertial sub-range风场wind site测量参数measurement parameters测量位置measurement seat最大风速maximum wind speed风功率密度wind power density风能密度wind energy density日变化diurnal variation年变化annual variation轮毂高度hub height风能wind energy标准大气状态standard atmospheric state风切变影响influence by the wind shear阵风影响gust influence风速频率frequency of wind speed环境environment工作环境operational environment气候climate海洋性气候ocean climate大陆性气候continental climate露天气候open-air climate室内气候indoor climate极端extreme日平均值daily mean极端最高extreme maximum年最高annual maximum年最高日平均温度annual extreme daily mean of temperature 月平均温度mean monthly temperature空气湿度air humidity绝对湿度absolute humidity相对湿度relative humidity降水precipitation雨rain冻雨freezing rain霜淞rime雨淞glaze冰雹hail露dew雾fog盐雾salt fog雷暴thunderstorm雪载snow load标准大气压standard air pressure平均海平面mean sea level海拔altitude辐射通量radiant flux太阳辐射solar radiation直接太阳辐射direct solar radiation天空辐射sky radiation太阳常数solar constant太阳光谱solar spectrum黑体black body白体white body温室效应greenhouse effect环境温度ambient temperature表面温度surface temperature互联interconnection输出功率output power额定功率rated power最大功率maximum power电网连接点network connection point电力汇集系统power collection system风场电器设备site electrical facilities功率特性power performance静电功率输出net electric power output功率系数power performance自由流风速free stream wind speed扫掠面积swept area轮毂高度hub height测量功率曲线measurement power curve外推功率曲线extrapolated power curve年发电量annual energy production可利用率availability数据组功率特性测试data set for power performance measurement 精度accuracy测量误差uncertainty in measurement分组方法method of bins测量周期measurement period测量扇区measurement sector日变化diurnal variations浆距角pitch angle距离常数distance constant试验场地test site气流畸变flow distortion障碍物obstacles复杂地形带complex terrain风障wind break声压级sound pressure level声级weighted sound pressure level; sound level 视在声功率级apparent sound power level指向性directivity音值tonality声的基准面风速acoustic reference wind speed 标准风速standardized wind speed基准高度reference height基准粗糙长度reference roughness length基准距离reference distance掠射角grazing angle风轮风轮wind rotor风轮直径rotor diameter风轮扫掠面积rotor swept area风轮仰角tilt angle of rotor shaft风轮偏航角yawing angle of rotor shaft风轮额定转速rated turning speed of rotor风轮最高转速maximum turning speed of rotor 风轮尾流rotor wake尾流损失wake losses风轮实度rotor solidity实度损失solidity losses叶片数number of blades叶片blade等截面叶片constant chord blade变截面叶片variable chord blade叶片投影面积projected area of blade叶片长度length of blade叶根root of blade叶尖tip of blade叶尖速度tip speed浆距角pitch angle翼型airfoil前缘leading edge后缘tailing edge几何弦长geometric chord of airfoil平均几何弦长mean geometric of airfoil气动弦线aerodynamic chord of airfoil翼型厚度thickness of airfoil翼型相对厚度relative thickness of airfoil厚度函数thickness function of airfoil中弧线mean line弯度degree of curvature翼型族the family of airfoil弯度函数curvature function of airfoil叶片根梢比ratio of tip-section chord to root-section chord 叶片展弦比aspect ratio叶片安装角setting angle of blade叶片扭角twist of blade叶片几何攻角angle of attack of blade叶片损失blade losses叶尖损失tip losses颤振flutter迎风机构orientation mechanism调速机构regulating mechanism风轮偏测式调速机构regulating mechanism of turning wind rotor out of the wind sideward变浆距调速机构regulating mechanism by adjusting the pitch of blade整流罩nose cone顺浆feathering阻尼板spoiling flap风轮空气动力特性aerodynamic characteristics of rotor叶尖速度比tip-speed ratio额定叶尖速度比rated tip-speed ratio升力系数lift coefficient阻力系数drag coefficient推或拉力系数thrust coefficient偏航系统滑动制动器sliding shoes偏航yawing主动偏航active yawing被动偏航passive yawing偏航驱动yawing driven解缆untwist塔架tower独立式塔架free stand tower拉索式塔架guyed tower塔影响效应influence by the tower shadow<<功率特性测试>>功率特性power performance净电功率输出net electric power output功率系数power coefficient自由流风速free stream wind speed扫掠面积swept area测量功率曲线measured power curve外推功率曲线extrapolated power curve年发电量annual energy production数据组data set可利用率availability精度accuracy测量误差uncertainty in measurement分组方法method of bins测量周期measurement period测量扇区measurement sector距离常数distance constant试验场地test site气流畸变flow distortion复杂地形地带complex terrain风障wind break声压级sound pressure level声级weighted sound pressure level视在声功率级apparent sound power level指向性directivity音值tonality声的基准风速acoustic reference wind speed标准风速standardized wind speed基准高度reference height基准粗糙长度reference roughness基准距离reference distance掠射角grazing angle比恩法method of bins标准误差standard uncertainty风能利用系数rotor power coefficient力矩系数torque coefficient额定力矩系数rated torque coefficient起动力矩系数starting torque coefficient最大力矩系数maximum torque coefficient过载度ratio of over load风力发电机组输出特性output characteristic of WTGS 调节特性regulating characteristics平均噪声average noise level机组效率efficiency of WTGS使用寿命service life度电成本cost per kilowatt hour of the electricity generated by WTGS 发电机同步电机synchronous generator异步电机asynchronous generator感应电机induction generator转差率slip瞬态电流transient rotor笼型cage绕线转子wound rotor绕组系数winding factor换向器commutator集电环collector ring换向片commutator segment励磁响应excitation response制动系统制动系统braking制动机构brake mechanism正常制动系normal braking system紧急制动系emergency braking system空气制动系air braking system液压制动系hydraulic braking system电磁制动系electromagnetic braking system机械制动系mechanical braking system辅助装置auxiliary device制动器释放braking releasing制动器闭合brake setting液压缸hydraulic cylinder溢流阀relief valve泻油drain齿轮马达gear motor齿轮泵gear pump电磁阀solenoid液压过滤器hydraulic filter液压泵hydraulic pump液压系统hydraulic system油冷却器oil cooler压力控制器pressure control valve压力继电器pressure switch减压阀reducing valve安全阀safety valve设定压力setting pressure切换switching旋转接头rotating union压力表pressure gauge液压油hydraulic fluid液压马达hydraulic motor油封oil seal刹车盘brake disc闸垫brake pad刹车油brake fluid闸衬片brake lining传动比transmission ratio齿轮gear齿轮副gear pair平行轴齿轮副gear pair with parallel axes 齿轮系train of gears行星齿轮系planetary gear train小齿轮pinion大齿轮wheel , gear主动齿轮driving, gear从动齿轮driven gear行星齿轮planet gear行星架planet carrier太阳轮sun gear内齿圈ring gear外齿轮external gear内齿轮internal内齿轮副internal gear pair增速齿轮副speed increasing gear增速齿轮系speed increasing gear train中心距center distance增速比speed increasing ratio齿面tooth flank工作齿面working flank非工作齿面non-working flank模数module齿数number of teeth啮合干涉meshing interference齿廓修行profile modification , profile correction 啮合engagement, mesh齿轮的变位addendum modification on gears变位齿轮gears with addendum modification圆柱齿轮cylindrical gear直齿圆柱齿轮spur gear斜齿圆柱齿轮helical gear single-helical gear节点pitch point节圆pitch circle齿顶圆tip circle齿根圆root circle直径和半径diameter and radius齿宽face width齿厚tooth thickness压力角pressure angle圆周侧隙circumferential backlash蜗杆worm蜗轮worm wheel联轴器coupling刚性联轴器rigid coupling万向联轴器universal coupling安全联轴器security coupling齿tooth齿槽tooth space斜齿轮helical gear人字齿轮double-helical gear齿距pitch法向齿距normal pitch轴向齿距axial pitch齿高tooth depth输入角input shaft输出角output shaft柱销pin柱销套roller行星齿轮传动机构planetary gear drive mechanism 中心轮center gear单级行星齿轮系single planetary gear train柔性齿轮flexible gear刚性齿轮rigidity gear柔性滚动轴承flexible rolling bearing输出联接output coupling刚度rigidity扭转刚度torsional rigidity弯曲刚度flexural rigidity扭转刚度系数coefficient of torsional起动力矩starting torque传动误差transmission error传动精度transmission accuracy固有频率natural frequency弹性联接elastic coupling刚性联接rigid coupling滑块联接Oldham coupling固定联接integrated coupling齿啮式联接dynamic coupling花键式联接splined coupling牙嵌式联接castellated coupling径向销联接radial pin coupling周期振动periodic vibration随机振动random vibration峰值peak value临界阻尼critical damping阻尼系数damping coefficient阻尼比damping ratio减震器vibration isolator振动频率vibration frequency幅值amplitude位移幅值displacement amplitude速度幅值velocity amplitude加速度幅值acceleration amplitude控制与监控系统远程监视telemonitoring协议protocol实时real time单向传输simplex transmission半双工传输half-duplex transmission双工传输duplex transmission前置机front end processor运输终端remote terminal unit调制解调器modulator-demodulator数据终端设备data terminal equipment接口interface数据电路data circuit信息information状态信息state information分接头位置信息tap position information监视信息monitored information设备故障信息equipment failure information 告警alarm返回信息return information设定值set point value累积值integrated total integrated value瞬时测值instantaneous measured计量值counted measured metered measured metered reading 确认acknowledgement信号signal模拟信号analog signal命令command字节byte位bit地址address波特baud编码encode译码decode代码code集中控制centralized control可编程序控制programmable control微机程控minicomputer program模拟控制analogue control数字控制digital control强电控制strong current control弱电控制weak current control单元控制unit control就地控制local control联锁装置interlocker模拟盘analogue board配电盘switch board控制台control desk紧急停车按钮emergency stop push-button限位开关limit switch限速开关limit speed switch有载指示器on-load indicator屏幕显示screen display指示灯display lamp起动信号starting signal公共供电点point of common coupling闪变flicker数据库data base硬件hardware硬件平台hardware platform层layer level class模型model响应时间response time软件software软件平台software platform系统软件system software自由脱扣trip-free基准误差basic error一对一控制方式one-to-one control mode一次电流primary current一次电压primary voltage二次电流secondary current二次电压secondary voltage低压电器low voltage apparatus额定工作电压rated operational voltage额定工作电流rated operational current运行管理operation management安全方案safety concept外部条件external conditions失效failure故障fault控制柜control cabinet冗余技术redundancy正常关机normal shutdown失效-安全fail-safe排除故障clearance空转idling外部动力源external power supply锁定装置locking device运行转速范围operating rotational speed range 临界转速activation rotational speed最大转速maximum rotational speed过载功率over power临界功率activation power最大功率maximum power短时切出风速short-term cut-out wind speed外联机试验field test with turbine试验台test-bed台架试验test on bed防雷系统lighting protection system外部防雷系统external lighting protection system内部防雷系统internal lighting protection system等电位连接equipotential bonding接闪器air-termination system引下线down-conductor接地装置earth-termination system接地线earth conductor接地体earth electrode环形接地体ring earth external基础接地体foundation earth electrode等电位连接带bonding bar等电位连接导体bonding conductor保护等级protection lever防雷区lighting protection zone雷电流lighting current电涌保护器surge suppressor共用接地系统common earthing system接地基准点earthing reference points持续运行continuous operation持续运行的闪变系数flicker coefficient for continuous operation 闪变阶跃系数flicker step factor最大允许功率maximum permitted最大测量功率maximum measured power电网阻抗相角network impedance phase angle正常运行normal operation功率采集系统power collection system额定现在功率rated apparent power额定电流rated current额定无功功率rated reactive power停机standstill起动start-up切换运行switching operation扰动强度turbulence intensity电压变化系数voltage change factor风力发电机端口wind turbine terminals风力发电机最大功率maximum power of wind turbine 风力发电机停机parked wind turbine安全系统safety system控制装置control device额定载荷rated load周期period相位phase频率frequency谐波harmonics瞬时值instantaneous value同步synchronism振荡oscillation共振resonance波wave辐射radiation衰减attenuation阻尼damping畸变distortion电electricity电的electric静电学electrostatics电荷electric charge电压降voltage drop电流electric current导电性conductivity电压voltage电磁感应electromagnetic induction 励磁excitation电阻率resistivity导体conductor半导体semiconductor电路electric circuit串联电路series circuit电容capacitance电感inductance电阻resistance电抗reactance阻抗impedance传递比transfer ratio交流电压alternating voltage交流电流alternating current脉动电压pulsating voltage脉动电流pulsating current直流电压direct voltage直流电流direct current瞬时功率instantaneous power有功功率active power无功功率reactive power有功电流active current无功电流reactive current功率因数power factor中性点neutral point相序sequential order of the phase 电气元件electrical device接线端子terminal电极electrode地earth接地电路earthed circuit接地电阻resistance of an earthed conductor 绝缘子insulator绝缘套管insulating bushing母线busbar线圈coil螺纹管solenoid绕组winding电阻器resistor电感器inductor电容器capacitor继电器relay电能转换器electric energy transducer电机electric machine发电机generator电动机motor变压器transformer变流器converter变频器frequency converter整流器rectifier逆变器inverter传感器sensor耦合器electric coupling放大器amplifier振荡器oscillator滤波器filter半导体器件semiconductor光电器件photoelectric device触头contact开关设备switchgear控制设备control gear闭合电路closed circuit断开电路open circuit通断switching联结connection串联series connection并联parallel connection星形联结star connection三角形联结delta connection主电路main circuit辅助电路auxiliary circuit控制电路control circuit信号电路signal circuit保护电路protective circuit换接change-over circuit换向commutation输入功率input power输入input输出output负载load加载to load充电to charge放电to discharge有载运行on-load operation空载运行no-load operation开路运行open-circuit operation 短路运行short-circuit operation 满载full load效率efficiency损耗loss过电压over-voltage过电流over-current欠电压under-voltage特性characteristic绝缘物insulant隔离to isolate绝缘insulation绝缘电阻insulation resistance 品质因数quality factor泄漏电流leakage current闪烙flashover短路short circuit噪声noise极限值limiting value额定值rated value额定rating环境条件environment condition 使用条件service condition工况operating condition额定工况rated condition负载比duty ratio绝缘比insulation ratio介质试验dielectric test常规试验routine test抽样试验sampling test验收试验acceptance test投运试验commissioning test维护试验maintenance test加速accelerating特性曲线characteristic额定电压rated voltage额定电流rated current额定频率rated frequency温升temperature rise温度系数temperature coefficient 端电压terminal voltage短路电流short circuit current可靠性reliability有效性availability耐久性durability维修maintenance维护preventive maintenance工作时间operating time待命时间standby time修复时间repair time寿命life使用寿命useful life平均寿命mean life耐久性试验endurance test寿命试验life test可靠性测定试验reliability determination test 现场可靠性试验field reliability test加速试验accelerated test安全性fail safe应力stress强度strength试验数据test data现场数据field data电触头electrical contact主触头main contact击穿breakdown耐电压proof voltage放电electrical discharge透气性air permeability电线电缆electric wire and cable电力电缆power cable通信电缆telecommunication cable油浸式变压器oil-immersed type transformer 干式变压器dry-type transformer自耦变压器auto-transformer有载调压变压器transformer fitted with OLTC 空载电流non-load current阻抗电压impedance voltage电抗电压reactance voltage电阻电压resistance voltage分接tapping配电电器distributing apparatus控制电器control apparatus开关switch熔断器fuse断路器circuit breaker控制器controller接触器contactor机械寿命mechanical endurance电气寿命electrical endurance旋转电机electrical rotating machine直流电机direct current machine交流电机alternating current machine同步电机synchronous machine异步电机asynchronous machine感应电机induction machine励磁机exciter饱和特性saturation characteristic开路特性open-circuit characteristic负载特性load characteristic短路特性short-circuit characteristic额定转矩rated load torque规定的最初起动转矩specifies breakaway torque交流电动机的最初起动电流breakaway starting current if an a.c. 同步转速synchronous speed转差率slip短路比short-circuit ratio同步系数synchronous coefficient空载no-load系统system触电；电击electric block正常状态normal condition接触电压touch voltage跨步电压step voltage对地电压voltage to earth触电电流shock current残余电流residual current安全阻抗safety impedance安全距离safety distance安全标志safety marking安全色safety color中性点有效接地系统system with effectively earthed neutral 检修接地inspection earthing工作接地working earthing保护接地protective earthing重复接地iterative earth故障接地fault earthing过电压保护over-voltage protection过电流保护over-current protection断相保护open-phase protection防尘dust-protected防溅protected against splashing防滴protected against dropping water防浸水protected against the effects of immersion过电流保护装置over-current protective device保护继电器protective relay接地开关earthing switch漏电断路器residual current circuit-breaker灭弧装置arc-control device安全隔离变压器safety isolating transformer避雷器surge attester ; lightning arrester保护电容器capacitor for voltage protection安全开关safety switch限流电路limited current circuit振动vibration腐蚀corrosion点腐蚀spot corrosion金属腐蚀corrosion of metals化学腐蚀chemical corrosion贮存storage贮存条件storage condition运输条件transportation condition空载最大加速度maximum bare table acceletation 电力金具悬垂线夹suspension clamp耐张线夹strain clamp挂环link挂板clevis球头挂环ball-eye球头挂钩ball-hookU型挂环shackleU型挂钩U-bolt联板yoke plate牵引板towing plate挂钩hook吊架hanger调整板adjusting plate花篮螺栓turn buckle接续管splicing sleeve补修管repair sleeve调线线夹jumper clamp防振锤damper均压环grading ring屏蔽环shielding ring间隔棒spacer重锤counter weight线卡子guy clip心形环thimble设备线夹terminal connectorT形线夹T-connector硬母线固定金具bus-bar support母线间隔垫bus-bar separetor母线伸缩节bus-bar expansion外光检查visual ins振动试验vibration tests老化试验ageing tests冲击动载荷试验impulse load tests 耐腐试验corrosion resistance tests 棘轮扳手ratchet spanner专用扳手special purpose spanner 万向套筒扳手flexible pliers可调钳adjustable pliers夹线器conductor holder电缆剪cable cutter卡线钳conductor clamp单卡头single clamp双卡头double clamp安全帽safety helmet安全带safety belt绝缘手套insulating glove绝缘靴insulating boots护目镜protection spectacles缝焊机seam welding machine。