当前位置：文档之家 › AERODYNAMICS AND AEROACOUSTICS OF AIRFLOW

AERODYNAMICS AND AEROACOUSTICS OF AIRFLOW

  • 格式：pdf
  • 大小：2.94 MB
  • 文档页数：15

AERODYNAMICS AND AEROACOUSTICS OF AIRFLOWOVER A HUMAN HEADFUYIN MA *,JIU HUI WU *,‡,FU GANG *,CHANG AN BAI †and LI QI †*School of Mechanical Engineering State Key Laboratory for Strength and Vibration of Mechanical Structure Xi’an Jiaotong University,Xi’an 71009†Shanghai HikeyTech,Inc.,Shanghai 200235‡ejhwu@ Received 29December 2013Revised 14March 2014Accepted 19March 2014Published 11April 2014Airflow should be affected by ear,nose,etc,and aerodynamic sound could be brought when the human head and the airflow occurs at a relative speed movement.Because the drag force of the head is large,in cycling competitions and other high-speed sport the diversion hats should be worn.After the speed of airflow reaches to a certain speed,due to the strong airflow inter-ference,the aerodynamic noise could be brought and it could greatly impact on the athletes to make action decisions.In this paper,computational fluid dynamics (CFD)method is used for solving the aerodynamic behavior of a human head under different air velocities,and the pressure on head surface and the airflow around the head are calculated.Then,the above-mentioned conditions of different aerodynamic sound are solved by the finite element/infinite element method (FEM/IFEM),the points in the canal entrance of the two ears are picked up for collecting the SPL spectral curves,and the sound distribution of the horizontal plane and the median plane are drawn.Previous studies showed that the aerodynamic noise brought by head spoiler is obvious at low frequencies,because the influence of the head,if the airflow speed is greater than a certain value,the aerodynamic noise could not only increase,but also should be substantially reduced.The results are useful for athlete diversion cap design and spatial hearing research in which the influence of the airflow should be considered.Keywords :Aerodynamic;aeroacoustics;human head;drag coefficient;CFD.1.IntroductionThe previous biomechanical study is mainly focused on the dynamics behaviors of bone joint motion,1,2the viscoelastic mechanical behavior of the muscle tissue,2mobility and rheological behavior of the blood of the cardiovascular system.How-ever,for the hydrodynamic behavior of the organism in the fluid (air and water)and the interaction with the fluid,when the relative movement occurs,the relative research is poor.Many sports projects involved faster relative motion between the human and air,such as sprinting,cycling race,skating competitions.A similarJournal of Mechanics in Medicine and BiologyVol.14,No.5(2014)1450068(15pages)°c World Scientific Publishing Company DOI:10.1142/S0219519414500687J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .situation also existed in water,especially when swimming,the body could be obstructed by water,and the score of the athletes are also affected.In fact,the \skin-like "swimsuit of the famous Olympic champion Michael Phelps aroused widespread interest,which is a typical example of combination of the fluid dynamics and human behaviors.In 1990,Ennos 3studied the unconventional air dynamic behavior of insects in flight,found the different lift mechanisms in Drosophila and other insects flying comparing with the lift generated by aircraft.There are also lots of studies regarding the aerodynamic and aeroacoustics of airflow over a subject,such as the aircraft disturbed by the airflow.4–8In 2005,Usherwood et al.9studied the mechanical behavior of greyhound racing at high speed,but did not consider the aspect of the aerodynamic.At present,some researches focused on the aerodynamic counter-attack damage by the flow behavior of the human body when the pilots worked in aircraft,through the drag coefficient of the head and limbs to evaluate the aero-dynamic behavior of the human body.10Such researches are generally done through wind tunnel testing on dummies,the purpose is to develop the deflector shields,play a protective role on the pilots.Fluid dynamics behavior in water is studied by more researchers.11–13The first aid is to optimize the performance of submarines and other underwater weapons through the bionics research,the other is to develop the low resistance swimsuit for athletes.Head especially ear plays a very important role to locate the sound source po-sition.Through the reflection of sound waves and other factors,the desired effect should be achieved to determine the position and distance of the sound source.14,15In the past,people studied the sound source localization effected by the head without considering the influence of the airflow.16However,in some special sports environment,the influence of the airflow is obvious.In addition,when the head is disturbed by the airflow,a great aerodynamic sound will generate at the higher airflow speed,which depends on the aerodynamic behavior of the head.In this paper,computational fluid dynamics (CFD)method is used for solving the aero-dynamic behavior of a human head under different air velocity,which is useful for athlete diversion cap design and spatial hearing research in which the influence of the airflow should be considered.2.Materials and Methods2.1.Model descriptionThe HRTF research is usually processed in an auditory spatial coordinates system,of which the origin is located at the midpoint of two ears,X -axis is pointed to the right side,Y -axis to the front side and Z -axis to the up side.There are three characteristic planes,which are the horizontal plane,median plane and lateral plane,as shown in Fig.1.We built a finite element method (FEM)solution model through a three-dimensional reverse head,in which the ears,nose and mouth areF.Ma et al.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .enclosed,and the impedance of the hair and skin is ignored i.e.,the overall head is rigid,the influence of the material is ignored and only the shape of the head is considered.The method of the aerodynamic sound solving requires an unsteady CFD tur-bulent calculation,and the element size of the CFD model needs to satisfy the following relationship between the steps of sampling time:U Át Áx %2:5;ð1Þwhere U is the fluid velocity,Át is the step of sampling time and Áx is the element size.For an acoustical FEM model,atleast six elements per wavelength are re-quired.So the upper frequency which the model can precisely consider is determined by the element size.The head surface is discreted by the triangular elements,and in order to get a more detailed expression for the geometric features of the auricles,the maximum element size of the head is 2mm,as shown in Fig.2(a).Create a cube space,in which the length is 1.3m,the width and height are 0.5m,each,and the origin of auditory coordinates is located in the midpoint of the two ears.Cube surface is discreted by triangular elements too,and the maximum element size is 20mm.Then the mesh of sound propagation space should be generated by the elements oftheFig.2.The mesh of the head and the fluidfield.Fig.1.Space coordinates of head.Aerodynamics and Aeroacoustics of Airflow Over a Human HeadJ . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .cube and head surface which is limited by the maximum size of 20mm,as shown in Fig.2(b).Thus,the CFD head model for the aerodynamic behavior solving is obtained,in which the solid elements constitute the fluid field region,the outermost cube boundary wall surface and the head rigid wall surface constitute the grid wall boundary.The model of Fig.2(b)is also used in acoustical calculation.The difference is that in the acoustic model,the outer wall of the cube is the infinite element surface,where the sound wave could propagate along the original path spread and without any reflection.Since the maximum element size of the entire model is 20mm,so according to the wavelength of six per unit to count,the model can be considered to 2820Hz.Calculation model based on the requirement of six elements per wave-length,divided into 1,791,864linear tetrahedral elements,solved the acoustic field distribution up to 2820Hz.2.2.The solving model and the boundary conditions In fluid field solving,the front side surface is set as the velocity inlet,and a velocity value is given;the behind side surface is set as the pressure outlet,a standard atmospheric pressure is generally given as the original pressure value,the around sides and the head surface are set as the rigid wall and the internal flow area is defined as the air material under normal temperature and pressure.The air is considered as incompressible fluid.Because the surface mesh of the head is dense enough,representing the influence of the boundary layer has been considered,and no boundary mesh added separately.The boundary conditions of the CFD model are shown in Fig.3.Three groups of velocity are selected as 5,12and 21m/s.One hundred steps of the steady iteration are calculated at first until the flow field to stabilize,then do not need to re-initialize the model and start the transient unsteady calculation.According to Eq.(1),at different wind conditions the time-step is different.Unsteady fluid field is solved by the k À"standard models,in-cluding the turbulent kinetic energy equation and the diffusion equation,the for-mula is as the following 17:@@t ð k Þþ@@x i ð k ui Þ¼@@x j þ t p r ;k @k @x jþG k þG b À "ÀY m þS k ;ð2ÞFig.3.The boundary conditions of the CFD model.F.Ma et al.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .@@t ð "Þþ@@x i ð "ui Þ¼@@x j þ t p r ;" @"@x jþC 1""k ðG k þC 3"G b ÞÀC 2" "2k þS ";ð3Þwhere G k is the turbulent kinetic energy generated by laminar flow velocity gradi-ent,G b is the turbulent kinetic energy generated by buoyancy,Y m is the fluctuation generated in compressible turbulence,C 1e ;C 2e and C 3e are some constant,p r ;k and p r ;"are the Prandtl number of the kinetic energy equation and diffusion equation,i and j are subscript,u i is the absolute velocity component in x i direction,c ui is the turbulent dissipation rate under u i ,k ui is the turbulent kinetic energy under u i ,s e is the component of the turbulence source term, is the dynamic viscosity.The model is solved by Fluent software in a normal workstation.Data of each solution step are required when solving the aeroacoustics,so we need to save each iteration results of unsteady iterative solution.Due to the number of elements in model is large,all the results not only should consume a lot of disk space,but also should lead to slow solution in the aeroacoustics solving,so just save the pressure data of each step.The points in the canal entrance of the two ears are picked up for collecting the SPL spectral curves,and the sound distribution of overall field could be obtained.Acoustic finite element analysis software Actran can complete the FFT trans-formation directly for unsteady field results obtained in the CFD solution,and transform the data into the frequency domain pressure fluctuations.Then through the Lighthill acoustic analogy method (corresponding to the low Mach number conditions),analogy aeroacoustics monopole,dipole sound source term can be obtained by the pressure fluctuations,and the sound distribution could be solved.The flow field is set to a Lighthill volume,the outer surface of the cube is set to an infinite element surface.The aeroacoustics solving model is as shown in Fig.4.Fig.4.The aeroacoustics solution model for Actran software.Aerodynamics and Aeroacoustics of Airflow Over a Human HeadJ . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .After an aeroacoustics solving,the sound distribution of various frequencies and the spectral curve of the sound pressure at any point of space can be obtained.The aeroacoustics calculation could cost lots of time,the more the computation itera-tions,the greater the time costs,while too little iterations can cause the instability results.In this study,three groups of velocity corresponding to the CFD calcula-tions are selected as5,12and21m/s.SPL spectral curves in the points in the canal entrance of the two ears are picked up,and the sound distribution sectional contours of some special frequency points are drawn.3.Results and Discussion3.1.The grid-independency testingIn order to validate the solution model,grid-independency is tested in this section. Because the solution accuracy of the aeroacoustics depend on the accuracy of the CFD solution,only the CFD model in different mesh densities is tested.There are three groups mesh density chosen,171,827,1,438,825and1,791,864elements,re-spectively.Figure5shows the mesh of these groups.The last group is used in later sections.For the condition with the velocity of21m/s,after1000times unsteady iteration with the time-step of0.0003s,Fig.6shows cross-sectionalflow velocity contours in the median pared the maximum velocity values of each group with Fig.7(c),it suggests that the results of thefirst group is very different with the results of the other two groups.It means the mesh density of thefirst group is not enough to complete the solution.And both the contours shape and the velocity values of the second and third groups are close to each other,so the mesh density of the last group is enough to support the later calculations.3.2.Fluidfield distributionIn order to obtain the change in theflowfield around the head more clearly,the cross-sectionalflow velocity contours of each given velocity of inlet conditionsin Fig.5.Three groups mesh density for these testing,171,827,1,438,825and1,791,864elements,respectively.F.Ma et al.J.Mech.Med.Biol.214.14.Downloadedfromwww.worldscientific.combyHUAZHONGUNIVERSITYOFSCIENCEANDTECHNOLOGYon6/22/15.Forpersonaluseonly.median plane and the pressure contours of head surface are drawn and as shown in Fig.7.From the velocity contours of Figs.7(a)–7(c),it suggests that with the increase of flow speed,the interference of the head and airflow become stronger.At 5m/s the entire flow field is disturbed by the head;when the velocity increases to 12m/s and 21m/s,only parts of flow field is more significantly disturbed,and at the top,local high velocity region appeared.Overall,mutual interference behaviors of the head and flow are obvious at the higher velocity,the closer the front face,the slower of the flow;at the top area,the closer to the head,the higher the flow;at the rear area,the closer to the head,the slower the flow.In addition,regardless of the speed is high or slow,a low-wake zone at the rear side could be generated.From the pressure contours of Figs.7(d)–7(i),it suggests that in the front face region of the head,the pressure is greater than in the top and rear regions,i.e.,the Fig.6.The cross-sectional flow velocity contours in the median plane of the first twogroups.(a)(b)(c)(d)Fig.7.The cross-sectional flow velocity contours of each given velocity of inlet conditions in the median plane and the pressure contours of the head surface.(a)Cross-sectional velocity contours at speed of 5m/s;(b)cross-sectional velocity contours at speed of 12m/s;(c)cross-sectional velocity contours at speed of 21m/s;(d)cross-sectional pressure contours at speed of 5m/s;(e)cross-sectional pressure contours at speed of 12m/s;(f)cross-sectional pressure contours at speed of 21m/s;(g)the pressure contours of head surface at speed of 5m/s;(h)the pressure contours of head surface at speed of 12m/s;(i)the pressure contours of head surface at speed of 21m/s.Aerodynamics and Aeroacoustics of Airflow Over a Human HeadJ . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .pressure of these regions is small.With the increase of the velocity,the pressure of the flow field becomes uniform,only the regions close to the head retain some uneven distribution.Further,from the figure,it also suggests that the pressure around the nose region is greater than other regions,i.e.,the influence of the airflow is more obvious;and the pressures of the auricle regions are relatively small,the influence of the airflow is weak.It indicates that the auricle structure of the aero-dynamic characteristics is relatively optimized compared with the overall head,so in the high-speed movement process it could not generate a greater additional re-sistance caused by the ear.3.3.Sound field distribution According to Eq.(1)the minimum allowable iteration time-step of CFD solution can be determined,and this step directly determines the cutofffrequency of theacoustical model.So at the speed of 5m/s,the minimum iteration step is 0.01s and the highest cutofffrequency of the acoustical model is 100Hz;at the speed of 12m/s,the minimum iteration step is 0.004s and the highest cutofffrequency is 250Hz;at the speed of 21m/s,the minimum iteration step is 0.002s and the highest cutofffrequency is 500Hz.For the sound field solution,the speed of 5m/s corre-sponds to the calculation frequency from 10–100Hz,steps by 2Hz;12m/s corre-sponds to the calculation frequency from 10–250Hz,steps by 5Hz;21m/s corresponds to the calculation frequency from 10–500Hz,steps by 5Hz.The bin-aural frequency response functions of the monitoring points are shown in Fig.8(a).(e)(f)(g)(h)(i)Fig.7.(Continued )F.Ma et al.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .The sensitivity frequency band of the auditory is mainly located in the range of 1000–5000Hz,especially from 1000Hz to 3000Hz.In order to obtain the sound field distribution of the higher frequency band,only the higher speeds of 12m/s and 21m/s conditions are solved up to cutofffrequency of 3000Hz.The binaural fre-quency response functions of the monitoring points are shown in Fig.8(b).(a)(b)Fig.8.The binaural frequency response functions of the monitoring points at different velocity condi-tions.(a)The results in different cut-offfrequency;(b)the results in upper cut-offfrequency of 3000Hz.Aerodynamics and Aeroacoustics of Airflow Over a Human HeadJ . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .Figure 8(a)suggests that the total SPL gradually increase with the decrease of frequency,and followed a stable trend.In the low frequency the SPL is very large,at 12m/s conditions,the maximum SPL reaches to 115dB.When the velocity increases from 5m/s to 12m/s,the SPL gradually increases with the speed below 100Hz;when the velocity increases to 21m/s further,the SPL decreases unsteadily.Furthermore,the figure also suggests that the SPL is greater in the low frequency ranges,and the SPL is lower in high frequency ranges,of which the human auditory is more sensitive to sound than other ranges.Just based on this characteristic,the SPL of the A-weighting is attenuated a lot in the low frequency ranges.In addition,except at 12m/s conditions,there exists a band where the SPL of left ear is smaller than the right ear,under the remaining frequencies,is greater than the SPL of the right ear,which is probably caused by vortex turbulence of the asymmetric flow field.Figure 8(b)suggests that the spectrum changes very largely above 400–500Hz,and appears as a significant valley.At 12m/s,the right ear appears as a deep valley at about 450Hz,whereas the left ear appears as a deep valley at about 1800Hz.At 21m/s,the left ear appears as deep valley at about 1300Hz.From the attenuation trends of the SPL,the value of SPL is no more than 80dB at 12m/s above 500Hz,and the minimum value is only 50dB;while at 21m/s,the maximum value islessFig.9.The sound distribution contours in the median and horizontal plane at 42,82and 100Hz with the velocity of 5m/s.Sound distribution contours in the median plane at (a)42Hz,(b)82Hz,(c)100Hz;sound distribution contours in the horizontal plane at (d)42Hz,(e)82Hz,(f)100Hz.F.Ma et al.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .than 40dB,the minimum reaches nearly to 0dB.This indicates that,on the one hand,the aerodynamic noise is mainly obvious in the low frequency ranges;on the other hand,since the influence of the head,when the airflow speed is greater than a certain value,the aerodynamic noise should not only increase,but also should be substantially reduced.In order to obtain the sound field distribution under different flow conditions at different frequencies,Fig.9shows the sound distribution contours in the median and horizontal planes at 42,82and 100Hz frequencies with the velocity of 5m/s;Fig.10shows the sound distribution contours in the median and horizontal planes at 55,155and 250Hz frequencies with the velocity of 12m/s and Fig.11shows the sound distribution contours in the median and horizontal planes at 55,255and 500Hz frequencies with the velocity of 21m/s.The figure indicates the spoiler role of the head dues to a large vortex appearing in front of the head of the sound field and a series of vortices in behind,similar to the horseshoe vortex of a flow field.In comparison,when the flow velocity is slow (5m/s),vortex distribution is more obvious in front and behind sides and exhibit both an obvious high sound pressure region and a low sound pressure region,the maximum SPL of the high sound pressure region exceeds 100dB,but the SPL of the low sound pressure region is less than 10dB.When the velocity becomehigherFig.10.The sound distribution contours in the median and horizontal plane at 55,155and 250Hz with the velocity of 12m/s.Sound distribution contours in the median plane at (a)55Hz,(b)155Hz,(c)250Hz;sound distribution contours in the horizontal plane at (d)55Hz,(e)155Hz,(f)250Hz.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .(21m/s),sound pressure distribution becomes more uniform in front of the head region,and behind of the head a higher sound pressure shaded region appears,and a low pressure zone appears behind of this shaded region.From the sound field dis-tribution in horizontal plane,it suggests that in the low speed condition,the sound field of the left and right sides are asymmetric;but in the high speed conditions,the sound field tends to symmetric.These results are also indicated from the frequency response curves of Fig.8,when the velocity reaches to 21m/s,the difference of the SPL between the two ears is small,barely 1dB.The numerical model of this study has been validated by the results reported in the literature,in which the airflow has not been considered.By comparing thecurves of Fig.8with the curves of Fig.12,it suggests that there are some similar trends of the binaural frequency response functions,such as the valley feature.However,the valley will move along the low frequency direction when the head is influenced by the airflow.In Fig.8,the first valley of the right ear at 12m/s is generated at 460Hz,and the first valley of the left ear at 12m/s is generated at 1800Hz,and the first valley of Fig.12is generated at 1900Hz.The first valley of the left ear is most close to the one of Fig.12.The main reason is that the sound source of this study is the aeroacoustic which is brought by airflow,but the sound source of Ref.14is a fixed plane-type soundwave.Fig.11.The sound distribution contours in the median and horizontal plane at 55,255and 500Hz with the velocity of 21m/s.Sound distribution contours in the median plane at (a)55Hz,(b)255Hz,(c)500Hz;sound distribution contours in the horizontal plane at (d)55Hz,(e)255Hz,(f)500Hz.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .4.Conclusions Through the aerodynamic sound field and CFD flow field calculation and analysis,the distribution of flow field and sound field can be summed up,including the following points:(1)The distribution of flow field indicates that with the increase of flow speed,the interference of the head and airflow become stronger.At high flow speed,the interference is obvious,showing offin front of the face,the closer to the face,the slower the airflow;in the top region,the closer to the head,the faster the flow;behind the head,the closer both head,the slower the speed.(2)With the increase of the velocity,the whole flow field pressure becomes uniform except the region near the head.This shows that the auricle structure of the aerodynamic characteristics is relatively optimized,and in the high-speed movement process they could not generate a greater additional resistancecaused by the ear.(3)From the binaural frequency response curves,it indicates that,on the one hand,the aerodynamic noise mainly distributes in the low frequency ranges;on the other hand,with the influence of the head structural characteristics,when the airflow is higher than a certain speed,aerodynamic noise should not continue to increase,but should be greatly reduced.In the low frequency ranges,with the less sensitive human auditory,noise level is relatively higher,in the medium and high frequency ranges,with the more sensitive human auditory,SPL is rela-tively lower.This rule is consistent with a weight of human auditoryexperience.Fig.12.A group HRTF data at 240 azimuth,in which the fixed sound source has been considered.The solid line and the dotted line show the results obtained by the source independent method and the newly proposed method in Ref.14,respectively.J . M e c h . M e d . B i o l . 2014.14. D o w n l o a d e d f r o m w w w .w o r l d s c i e n t i f i c .c o mb y H U A Z H O N G U N I V E R S I T Y O F S C I E N C E A N D T E C H N O L O G Y o n 06/22/15. F o r p e r s o n a l u s e o n l y .。

合集下载

Airfoil Aerodynamics：翼型的空气动力学PPT

Airfoil Aerodynamics：翼型的空气动力学PPT

• German Aerospace Center
Purpose
• The purpose of this experiment is to lower the drag and increase the lift as well as delaying the stall angle of a model airfoil by applying vortex generators or ribleting the surface to lower skin friction drag, as well as producing self induced vibrations with a spanwise wire.
• Aerodynamic Forces • How an Airfoil
Drag Equation
Generates Lift
Lift Equation
Benson, 2007
• Stall
Knowledge Base
• Reynold’s Number
Literature Review
• CFD Simulations of Oscillating Sub-Boundary Layer Vortex Generators for Diffuser Flow Separation Control, Amhad 2021
• International Journal of Engineering and Technology
Scott, 2005
Literature Review
• Effects of Surface Roughness and Vortex Generators on a NACA Airfoil, Ruess 1995
Aerodynamics,aeronautics,andflightmechanics

Aerodynamics,aeronautics,andflightmechanics

Aerodynamics Aeronautics And Flight Mechanics9780471575061: Aerodynamics, Aeronautics, and FlightA New Edition of the Most Effective Text/Reference in the Field! Aerodynamics, Aeronautics, and Flight Mechanics, Second Edition Barnes W. McCormick, Pennsylvania/9780471575061/Aerodynamics-Aeronautics-Flight-Mechanics-McCormick-0471575062/plpAerodynamics, aeronautics and flight mechanics by BarnesDesigned for introductory courses in aerodynamics, aeronautics and flight mechanics, this text examines the aerodynamics, propulsion, performance, stability and/Aerodynamics-aeronautics-and-flight-mechanics-Barnes-Warnock-McCormick/book/151602Aerodynamics, Aeronautics, and Flight Mechanics 2nd EditionAerodynamics, Aeronautics, and Flight Mechanics | 9780471575061 | 0471575062 | McCormick, Barnes W. | Books | /textbooks/aerodynamics-aeronautics-and-flight-mechanics-2nd-edition/9780471575061aerodynamics aeronautics and flight mechanics solutions manualDo You Want To See More Details About "aerodynamics aeronautics and flight mechanics solutions manual"? Then Ask Here with your need/request , We will collect and/s/aerodynamics-aeronautics-and-flight-mechanics-solutions-manualAerodynamics aeronautics and flight mechanics - London GroupWhich allows flight mechanics , john d phylogenetically 5-9 to subsonic to specific. 2nd ed., john wing theory, lift and wake. Aeronautics, mechanics lift and/aerodynamics-aeronautics-and-flight-mechanics/aerodynamics aeronautics and flight mechanicsDo You Want To See More Details About "aerodynamics aeronautics and flight mechanics"? Then Ask Here with your need/request , We will collect and show specific/z/aerodynamics-aeronautics-and-flight-mechanics: Aerodynamics, Aeronautics, and Flight MechanicsTry Prime. Your Today's Deals Gift Cards Sell Help. Shop by Department/s?ie=UTF8&page=1&rh=i%3Aaps%2Ck%3AAerodynamics%5Cc%20 Aeronautics%5Cc%20and%20Flight%20MechanicsAerodynamics aeronautics and flight mechanics - GehringForces and course taught at aerodynamics hydrodynamics. Range which allows flight. In 320 introd/aerodynamics-aeronautics-and-flight-mechanics/Aerodynamics aeronautics and flight mechanics - SlideShareNov 07, 2013 CONTENTS ONE INTRODUCTION A Brief History A Brief Introduction to theTechnology of Aeronautics TWO FLUID MECHANICS Fluid Statics and the Atmosphere Fluid /tamilaghil/aerodynamics-aeronautics-and-flight-mechanicsAerodynamics, Aeronautics and Flight Mechanics by Barnes WBarnes & Review Rules. Our reader reviews allow you to share your comments on titles you liked, or didn't, with others./w/aerodynamics-aeronautics-and-flight-mechanics-barnes-w-mccormick/1102286150?ean=9780471030324Home : The American Institute of Aeronautics and AstronauticsFeaturing 16 Technical Conferences AVIATION 2015 will deliver a strong technical Atmospheric Flight Mechanics The American Institute Of Aeronautics Andhttps:///Aerodynamics, Aeronautics and Flight Mechanics : Barnes WAerodynamics, Aeronautics and Flight Mechanics by Barnes W. McCormick, 9780471575061, available at Book Depository with free delivery worldwide./Aerodynamics-Aeronautics-Flight-Mechanics-Barnes-McCormick/9780471575061Aerodynamics aeronautics and flight mechanics | SkeyI can wholeheartedly and without reservation recommend Gerald Skey as an attorney. He is a lawyer of the highest caliber and integrity with extensive experience/aerodynamics-aeronautics-and-flight-mechanics/Aerodynamics, Aeronautics, And Flight Mechanics - ReviewsYahoo! Shopping is the best place to comparison shop for Aerodynamics Aeronautics And Flight Mechanics. Compare products, compare prices, read reviews and merchanthttps:///9780471575061-aerodynamics-aeronautics-and-flight-mechanics/; _ylt=AwrBT82zxCNVuroA1YtXNyoA;_ylu=X3oDMTBzaWxuc3BzBGNvbG8DYmYxBHBvcwMx NgR2dGlkAwRzZWMDc3I-Introduction to Aeronautical Engineering | edXDiscover the fascinating world of aviation by investigating aeronautics, with a closer look at aerodynamics and flight mechanics.https:///course/introduction-aeronautical-engineering-delftx-ae-1110xRelated PDF manuals Download:Download Engineering thermodynamics atul prakashan.pdfDownload Short stories with high frequency words.pdfDownload Checkpoint exam papers.pdfDownload Jeffrey richter windows application programming.pdfDownload Chemical kinetics quest questions.pdfDownload August daycare calendar.pdfDownload Deep connection kezia noble.pdfDownload Asthma action plan for children template.pdfDownload Sheet music armstrong.pdfDownload Ward solid mechanics.pdfMore manual PDF Files:Download Nursing process flowchart.pdfDownload American flag wrapping paper.pdfDownload Bullying skit for two people.pdfDownload Real time systems kvkk prasad.pdfDownload John kingdon agendas alternatives and public policies.pdf Download Side impact rollover.pdfDownload Penthouse letter form.pdfDownload Mirtone fire alarm mir2 dialer.pdfDownload Science spot energy resources scavenger hunt answers.pdf Download Mezmure dawit ethiopian orthodox church.pdfsitemap。

航空专业技术词汇英汉对照

航空专业技术词汇英汉对照

航空专业技术词汇英汉对照一、飞机设计Absolute ceiling 绝对升限Absolute similarity 完全相似Active laminar flow control 主动层流控制Adiabatic exponent 绝热指数Adiabatic flow 绝热流Adjustable tab 调整片Advance ratio(ration) 前进比Advancing blade 前行桨叶Adverse pressure gradient 逆压梯度Aerial survey airplane 航测飞机Aerobatics 特技飞行术Aerodynamic brake, airbrake flap 减速板Aerodynamic center 气动中心Aerodynamic coefficient 空气动力系数Aerodynamic compensation 气动补偿Aerodynamic derivative 气动导数Aerodynamic heating 气动加热Aerodynamic retardation 气动阻滞Aerodynamic twist 气动扭转Aerodynamical interference 空气动力干扰Aerodynamics 空气动力学，空气动力特性Aeroelastic effect test 气动弹性试验Aeroelasticity 气动弹性力学Aerogator （口语）领航员Aerohydroplane 水上飞机Aeroplane 飞机Aerospace vehicle 宇航飞行器Aft center of gravity limit 重心后限Agricultural aircraft 农业机Aileron 副翼Air filter 空气滤Air flap 鱼鳞片（或风门片）Air intake test 进气道试验Air refueling aircraft 空中加油机Air superiority fighter 空中优势战斗机Air superiority mission 占领制空权任务Air-carrier aircraft 民航飞机，运输机Air-cushion landing gear 气垫式起落架Air-interception aircraft 截击机Air-trajectory reference frame 气流坐标系Airborne early warning and control aircraft 空中预警引导机（发出预警并引导战斗机）Aircraft air conditioning system 飞机空气调节系统Aircraft wheel 机轮Airflow pulsation 气流脉动Airfoil 翼型Airfoil thickness 翼型厚度Airfoil with reverse camber 反弯度翼型Airplane 飞机Airship 飞艇Airspeed 空速All-cargo aircraft 货机All-movable stabilizer 全动平尾All-moving fin 全动垂尾All-weather aircraft 全天候飞机All-wing aircraft 飞翼，飞翼式飞机Ambulance aircraft 救护机Amphibian 水陆两用机Amphibian/amphibious aircraft 水陆两用飞机Angle of attack 迎角Angle of climb 航迹倾斜角Annular wing 环翼Anti-submarine warfare aircraft 反潜机Applied brake time 刹车时间Apply aileron 偏转副翼Arc tunnel 电弧风洞Area rule 面积率Arrow wing 箭形翼Articulated landing gear 摇臂式起落架Artificial transition 人工转换Artillery observation aircraft 炮兵校射机Aspect ratio 展弦比Assault aircraft 强击机，机降突击运输机（美）Associated mass 连续质量Atmosphere 大气Attacker 强击机（攻击机）Auto rotation 自转Auto-stabilizer 增稳器Autogyro 旋翼机Automatic antiskid brake system 自动防滑刹车系统Autorotation state 自旋状态Available fuel consumption 可用燃油量Available power 可用功率Available power of helicopter 直升机可用功率Available thrust 可用推力Avoid shaded area 回避区Axis system 坐标轴系Axisymmetrical flow 轴对称流Backswept wing aircraft 后掠翼飞机Balance weight 配重Bank 坡度Barotropic fluid 正压性流体Base drag 底部阻力Bernoulli’s equation 伯努利方程Bernoulli’s theorem 伯努利定理Bicycle landing gear 小车式起落架Big aircraft 重型飞机Bimotor aircraft 双发发动机飞机Biplane 双翼机Blade azimuth angle 桨叶方位角Blade element theory 叶素理论Blade geometric twist 桨叶几何扭转Blade section pitch 桨叶剖面安装角Blade tip-root loss factor叶端损失系数Blade-vortex interaction桨涡干涉Blended wing body 翼身融合体Blockage effect 阻塞效应Blown flap 吹气襟翼Bobtailed aircraft 无尾飞机Body 机身Body-fixed reference frame 机体坐标系Bogie landing gear 小车式起落架Bombardment aircraft 轰炸机Bound vortex 附着涡Boundary condition 边界条件Boundary layer 附面层Boundary layer control 附面层控制Boundary layer thickness 附面层厚度Brake control box 刹车控制盒Brake disc 刹车盘Brake efficiency coefficient 刹车效率系数Brake running distance 刹车滑跑距离Brake running time 刹车滑跑时间Brake speed 刹车速度Brake torque 刹车力矩Braking energy 刹车能量Breakout force 起动力Bubble 气泡Buffeting 抖振Buffeting test 抖振试验Bulkhead 隔框Buoyancy 浮力Buoyancy correction 浮力修正Cabin air pressure control system 座舱压力调节系统Cabin air pressure discharge valve 座舱排气活门Cabin air supply flow rate 座舱供气量Cabin altitude 座舱高度Cabin leakage 座舱泄露Cabin pressure difference 座舱剩余压力Cabin pressure inflow safety valve 座舱负压活门Cabin pressure regulator 座舱压力调节器Cabin silencer 座舱消音器Cabin ventilation 座舱通风Calibrated airspeed 校正空速Calibration-model test 标准模型试验Camber 弯度Canard aircraft 鸭式飞机Canard configuration 鸭式布局Canard surface flaps 鸭式前置翼面襟翼Canopy 座舱盖Cargo aircraft 货机Carried-body test 携带试验Carrier-based plane 舰载飞机Cascade wind tunnel 叶栅风洞Cathedral angle 下反角Ceiling 升限Center of gravity 重心Chandelle 战斗转弯Characteristics of mode 模态特性Choke-out （风洞）壅塞Circulation 环量Civil airworthiness requirements 民用适航性要求Civil or military design specification 民用军用设计规范Climb 爬升Climb rate 爬升率Close-support aircraft 近距空中支援机Closed-circuit wind tunnel 回流式风洞Coaxial propellers 共轴桨Coaxial twin rotor helicopter 共轴式双旋翼直升机Cockpit cover 座舱盖Coefficient of viscosity 粘性系数Collective-pith control 总距控制Combat turn 战斗转弯Combat-and-trainer aircraft 战斗教练机Compensator 补偿装置Composite aircraft 子母机Composite helicopter 组合式直升机Compound helicopter 复合式直升机Compressibility 可压缩性Compression wave 压缩波Conceptual design 概念设计Conceptual sketch 概念草图Configuration 结构型式Conical camber 锥形弯曲Conical flow 锥形流Conical twist 锥形扭转Constant pressure difference control 等压差调节Constant-speed propeller 恒速桨Continuity 连续性Continuous wind tunnel 连续式风洞Continuum 连续介质Contra-rotating propellers 共轴桨Contraction cone(section) 收缩段Control 操纵或控制调节Control column 驾驶杆Control configured vehicle 随控布局飞机Control deflection 操纵面偏角Control displacement 驾驶位移Control force 操纵力Control stick 驾驶杆Control surface 操纵面Control tab 操纵片Control-fixed 握杆Control-free 松杆Controllability 操纵性Conventional(design) aircraft 常规（布局）飞机Convertible aircraft 推力换向式飞机，客货可易性飞机Coordinate system 坐标系Counter weight 配重Countermeasures aircraft 干扰飞机，电子对抗飞机Covering 蒙皮Cowling 整流罩Critical Mach number 临界马赫数Critical Reynolds number 临界雷诺数Critical section 临界截面Cross derivative 交叉导数Cross-wind landing 侧风着陆Cross-wind take-off 侧风起飞Cruise 巡航Cruise range 巡航范围Cruising speed 巡航速度Cryogenic wind tunnel 低温风洞Cyclic pitch control 周期变距操纵Cylinder piston housing 气缸座Damped vibration 阻尼振动Data process 数据处理Deck-based aircraft 舰载飞机Decompression accelerator 减压加速度Deep stall 深度失速Delta wing 三角形机翼Density 密度Departure 失控过渡Depress the aileron 使副翼向下偏转Descent 下降Design analysis 设计分析Design concept 设计概念Design lift coefficient 设计升力系数Design requirement 设计规范Detail design 详细设计Diamond region of test section 试验段菱形区Differential aileron 差动副翼Diffuser 扩压段Dihedral angle 上反角Dimensional theory 量纲理论Directional control 航向控制Directional stability 航向稳定性Directional static stability 横侧稳定性Disc area 桨盘面积Disk plane 桨盘平面Distance of landing run 着陆滑跑距离Distance of take-off run 起飞滑跑距离Disturbance 扰动Dive 俯冲Dog tooth 犬齿（锯齿）Dorsal fin 背鳍Double cavity landing gear 双腔式起落架Double delta wing 双三角翼Doublet 偶极子Downwash 下洗Downwash correction 下洗修正Draft 吃水Drag 阻力Drag coefficient 阻力系数Drag divergence 阻力发散Drag due to lift 升致阻力，感应阻力，诱导阻力Drone aircraft 无人驾驶飞机，靶机Drop test 地面落震试验Droppable fuel tank 副油箱Ducted propeller 函道螺桨Duplicated aileron 双段副翼Dutch roll 荷兰滚Dutch roll mode 荷兰滚模态Dynamic ceiling 动升限Dynamic derivative 动导数Dynamic pressure 速压，动压Dynamic stability 动稳定性Dynamic test 动力试验Dynamics derivative test 动导数试验Dynamics stability 动稳定性Early warning aircraft 预警机Earth axis 地面坐标系Earth’s atmosphere 大气层Earth-fixed reference frame 地面坐标系Effective angle of attack 有效迎角Effective Reynolds number 有效雷诺数Elastic limit 弹性极限Electronic counter-measures aircraft 电子干扰飞机Elevator 升降舵Elongated aircraft 升降舵偏角/gEmergency door 应急舱门Empenage 尾翼Endurance 续航时间Energy equation 能量方程Entralpy 焓Entropy 熵Equation of continuity 连续性方程Equation of motion 运动方程Equation of state 状态方程Equilibrium 平衡Equivalent airspeed 当量空速Expansion wave 膨胀波Experiment data reduction 试验数据处理Experimental aerodynamics 实验空气动力学Extension mechanism 收放机构External stores test 外挂物试验Factor of safety 安全系数Fail-safe design 破损安全设计Fairing 整流罩False spar 纵墙Fatigue 疲劳Fatigue limit 疲劳极限Fatigue load 疲劳载荷Fatigue test 疲劳试验Feathering motion 变距运动Fighter 战斗机Fighter bomber 战斗轰炸机Fillet 整流片，整流包皮（两个面结合处的）Fin 垂直安定面Final approach 终进场Final assembly process 总装Finite element method 有限元素法First law of therme dynamics 热力学第一定律Five-digit series airfoils 五位数翼型Fixed trimmer 修正片Fixed trimming tab 修正片（固定调整片）Flap 襟翼Flaperon 襟副翼Flare 拉平段Flare out landing 拉平着陆Flare-out 着陆拉平Flick roll 急横滚Flight attitude 飞行姿态Flight control actuator 舵机Flight control system 飞行操纵系统，飞行控制系统Flight dynamics 飞行动力学Flight envelope 飞行包线Flight path axis 航迹坐标系Flight performance 飞行性能Flight profile 飞行剖面Flight test 飞行试验Flight-path angle 航迹倾斜角Flight-path axis 航迹坐标系Flight-path track angle 航迹转弯角Float 平飞减速段Float-tube landing gear 浮筒式起落架Flood ability 抗沉性Flow field 流场Flow field calibration 流场校正Flow pattern 流谱Flow quality 流场品质Flow visualization 流谱观察试验Fluid 流体Fluid dynamics 流体动力学Fluid particle 流体质点Fluid tube 流管Flutter 颤振Flutter test颤振试验Flying boat 水上飞机Flying quality 飞行品质Flying wing 飞翼Force test 测力试验Form drag 型阻Forward center of gravity limit 重心前限Forward flight 前飞Forward-retracting gear 前收式起落架Four-digit series airfoils 四位数翼型Fowler flap 富勒襟翼Fracture mechanics 断裂力学Frame 隔框Free stream 自由流Free vortex 自由涡Free-flight test 自由飞试验Fuel consumption per hour 小时耗油量Fuel consumption per kilometer 公里耗油量Fuel tank 油箱Fuel weight 油重Full scale wind tunnel 全尺寸风洞Full-scale development proposal 总体设计方案Fuselage 机身G overloading 过载Gas constant 气体常数Gearing ratio 传动比Geometric twist 几何扭转Get-away speed 离水速度Glide 下滑段Glide ratio 下滑比Glider 滑翔机Go around 复飞Gross weight 总重Ground effect 地面效应Ground effect test 地面效应试验Ground resonance 地面共振Ground run 地面滑跑段Ground speed 地速Ground-air-ground load 地空地载荷Guide plate 折流板Gull tape wing 海鸥式机翼Gun tunnel 炮风洞Gust 突风，阵风Gust load 突风载荷Half-model testing 半模型试验Hammerhead stall 失速翻滚特技Heat barrier热障Heat shield 隔热屏Heat transfer coefficient 传热系数Helicopter 直升机High Reynolds number wind tunnel 高雷诺数风洞High-lift device 增升装置High-speed wind tunnel 高速风洞Hinge moment 铰链力矩Hinge-moment test 铰链力矩试验Homoentropic flow 均熵流Honeycomb sandwich structure 蜂窝夹层结构Hook’s law 胡克定律Horizontal acceleration and deceleration capacity 水平加减速性能Horizontal flight 水平飞行Horizontal tail 水平尾翼Horse-shoe vortex 马蹄涡Horsepower loading 马力载荷Hospital or ambulance airplane 救护机Hot-wire anemometer 热线风速仪Hovercraft 气垫飞行器Hovering 悬停Hovering ceiling 悬停升限Hub 桨毂Hybrid platform wing 混合平面形状机翼Hydrodynamic performance水动性能Hydrodynamics 流体动力学Hypersonic flow 高超音速流Hypersonic shock layer 高超音速激波层Icing wind tunnel 结冰风洞Ideal fluid 理想流体Ideal gas 理想气体Immelmann turn 战斗半径Impact load 撞击载荷Impact pressure 撞击压力Inboard/inner aileron 内侧副翼，副翼内段Incompressible fluid 不可压缩流体Indicated airspeed 指示空速Induced drag 诱导阻力Inertial coupling 惯性耦合Inertial transducer 惯性传感器Inflow ratio 内流比，入流比Insubmersibility 抗沉性Integral fuel tank 整体油箱Integral structure 整体结构Interactions of balance system 天平干扰系统Interceptor 截击机Interference drag 干扰阻力Intermeshing rotor helicopter 交叉式双旋翼直升机Intermittent wind tunnel 暂冲式风洞Internal energy 内能Inverted flight 倒飞Isentropic flow 等熵流Jet airplane 喷气式飞机Jet flap 喷气襟翼Jet test 喷流试验Jettison test 投放试验KarMan V ortex street 卡门涡街Kinematic viscosity 运动粘性系数Krueger flap 克鲁格襟翼Lag 时滞Lag of wash 洗流时差Lagging motion 摆振运动Lambda shock lambda 波Laminar boundary layer 层流附面层Laminar flow 层流Laminar flow control 层流控制Laminar separation 层流分离Laminar-flow airfoil 层流翼型Landing 着陆Landing distance 着陆距离Landing gear 起落架Landing impact 着陆撞击Landing sink-speed 着陆下滑速度Landing speed 着陆速度Lateral control 横向操纵Lateral stability 横向稳定性Lateral static stability 横向静稳定性Laval nozzle 拉瓦尔喷管Leading edge 前缘Leading edge flap 前缘襟翼Leading edge radius 前缘半径Leading-edge notch 锯齿Leading-edge slot 前缘缝翼Leading-edge suction 前缘吸力Left rotation propeller 反转桨Level flight ceiling 平飞升限Lift coefficient 升力系数Lift dumper 扰流板Lift effect 升力效应Lift-drag ratio 升阻比Lifting rotor 旋翼Lifting-line theory 升力线理论Lifting-surface theory 升力面理论Limit load 载荷极限Linearized theory 线化理论Load 载荷Load factor 载荷因子Load feel unit 载荷感觉机构Load spectrum 载荷谱Lockout deboost valve 锁闭减压阀Longeron 桁梁Longeron fuselage 梁式机身Longitudinal beam 纵梁Longitudinal control 纵向操纵Longitudinal motion 纵向运动Longitudinal stability 纵向稳定性Loop 斤斗Low density wind tunnel 低密度风洞Low-level high-speed flight 地空高速飞行Low-level strike mission 地空攻击任务Low-speed wind tunnel 地速风洞Lowering mechanism 收放机构Ludwieg tube 路德维希风洞Mach cone 马赫锥Mach number 马赫数Mach wave 马赫波Magnetic balance 磁悬挂天平Magnetofluid dynamics 磁流体动力学Man powered aircraft 人力飞机Maneuver 机动飞行Maneuver flap 机动襟翼Maneuver load 机动载荷Maneuver point 机动点Maneuver-flap 机动襟翼Maneuverability 机动性Mathematical simulation 数学模拟Maximum lift coefficient 最大升力系数Maximum speed 最大速度Mean aerodynamic chord 平均气动弦Mean geometric chord 平均几何弦Mean increase of resistance in waves 波浪中阻力平均增量Mean wetted length 平均浸湿长度Mechanical type balance 机械式天平Medium 介质Method of singularitics 线化理论Military transport aircraft 军用运输机Minimum drag 最小阻力Minimum speed 最小速度Mode 模态Model 模型Model support 模型支架Momentum method 动量法Monocoque fuselage 硬壳式机身Monocoque wing 硬壳式机翼Monoplane 单翼机Multi-purpose fighter 多用途战斗机Multi-rotor helicopter 多旋翼式直升机NACA airfoil profiles NACA翼型Nacelle 短舱Neutral point 中性层Noise 噪音Nose 机头Nose cone/dome 机头罩Nosewheel landing gear 前三点式起落架Oblique wing 斜机翼One-dimensional flow 一维流Open-circuit wind tunnel 开路式风洞Operation radius 活动半径Optical measurement testing method 光测法Optimization 优化Optimization design 优化设计Ornithopter 扑翼机（振翼机）Outboard/outer aileron 外侧副翼，副翼外段Overall shaping 草图设计Pancake landing 平坠着陆Panel 壁板Parasite drag 废阻力Partial similarity 部份相似Particular military requirement 特殊军事要求Passenger aircraft 旅客机Path line 迹线Pay load 有效载荷Peaky airfoil profile 尖峰翼型Percentage of blockage 阻塞度Perfect fluid 完全流体Perfect gas 完全气体Performance 性能Performance parameters 性能参数Photometry 光测Phugoid mode 沉浮模态Physical simulation 物理模拟Pilotless aircraft 无人驾驶飞机Pilots’ outside vision angles 飞行员视角Piston engine airplane 活塞式飞机Pitching 俯仰Pitching moment 俯仰力矩Piton tube 皮托管Piton-static tube 风速管Plain flap 简单襟翼Plenum chamber 驻室Pneumatic storage bottle 冷气瓶Podded nacelle rack 发动机吊挂Poisson’s ratio 泊松比Polar 极曲线Power required 需用功率Power required of helicopter 直升机需用功率Power rogallo-wing craft 伞翼飞机Power-off stall 无动力失速Pressure 压强Pressure center 压力中心Pressure drag 压差阻力Pressure reducing valve 减压阀Pressure test 测压试验Pressure-control valve 调压阀Pressurized cabin 气密舱Pressurized wind tunnel 压力风洞Primary design 初步设计Production design 生产设计，施工设计Profile meanline 翼型中弧线（翼型中线）Propeller 螺旋桨Propeller blade angle 桨叶角Propeller disk area 螺旋桨桨盘面积Propeller disk loading 螺旋桨桨盘载荷Propeller efficiency 螺旋桨效率Propeller feathering 顺桨Proportional limit 比例极限Pursuit airplane 歼击机Quasi-steady assumption 准定常假设Radio-controlled aircraft 遥控飞机Radius of action 活动半径Raising/lowering mechanism 收放机构Random vibration 随机振动Range 航程Rarefied gas 稀薄气体Rate of advance 进矩比，前进比Rate of climb 爬升率Real gas 实际气体Reconnaissance aircraft 侦察机Recorder 记录器Rectangular wing 矩形机翼Rectified airspeed 校正空速Reference frame 坐标轴系Reflection of waves 波的反射Reformation 变形Reject take-off 中止飞行Relativity principle 相似性原理Remotely piloted vehicle 遥控飞机Reserve fuel 储备燃油Retraction/extension mechanism 收放机构Retreating blade 后行桨叶Reversal flow area 反流区Reversement 反航向特技Reversible-pitch propeller 反矩桨Reynolds number 雷诺数Ring 隔框Rise motion 升沉运动Roll 滚转Rolled-up vortex 卷起涡Rolling moment 滚转力矩Rotational flow 有旋流Rotor 旋翼Rotor aerodynamic efficiency in hovering 悬停时旋翼气动效率Rotor angle of attack 旋翼迎角Rotor brake system 旋翼刹车系统Rotor coning angle 旋翼锥度角Rotor disk loading 旋翼桨盘载荷Rotor down-wash angle 旋翼下洗角Rotor solidity 旋翼实度Rotor theory 旋翼理论Rotor thrust 旋翼推力Rotor torque 旋翼扭矩Rotor vortex system 旋翼涡系Rudder 方向舵Rudder pedals 脚蹬机构S-N curve S-N曲线Safe-life design 安全寿命设计Sailplane 滑翔机Sandwich structure 夹层结构Saw cut 锯口Scale effect 尺度效应Seakeeping 耐波性Sealed cabin 密封舱Seaplane 水上飞机Seaplane take-off taxing time and distance 水上飞机起飞滑跑时间和距离Search and rescue aircraft 救援机Seaworthiness 适航性Second law of thermodynamics 热力学第二定律Second throat 第二喉道Section of propeller blade 桨叶剖面Semi-monocoque fuselage 桁条式机身Semiattached body axis 半机体坐标系Separation 分离Service ceiling 实用升限Servo tab 弹簧补偿片Servo-compensator 随动补偿片Settling chamber 稳定段Settling section 安定段Shell wing 单块式机翼Shimmy damper 减摆器Ship-board plane 舰载飞机Shock absorber 缓冲器Shock stall 激波失速Shock tube wind tunnel 激波管风洞Shock wave 激波Shock wave-boundary layer interaction 激波附面层干扰Short-period mode 短周期模态Short-range take-off and landing plane 短距起落飞机Side force 侧力Side-by-side rotor helicopter 横列式双旋翼直升机Side-stick controller 侧杆操纵器Sideslip 侧滑Similarity criterion 相似准则Similarity law 相似率Similarity phenomenon 相似现象Similarity theory 相似理论Simple cruise mission 巡航任务Simulation test 模拟试验Single-rotor helicopter 单旋翼直升机Six-digit series airfoils 六位数翼型Skid-landing gear 滑橇式起落架Skimmy damper 减摆器Skin 蒙皮Slat 前缘缝翼Slender wing 细长翼Slip 侧滑Slip stream 滑流Slope of lift curve 升力线斜率Slot 翼缝Slot-tip/slotted aileron 开缝副翼Slotted flap 开缝襟翼Slow roll 慢横滚Small disturbance 小干扰Smoke wind tunnel 烟风洞Snap roll 急横滚Sonar 声纳Sonic barrier 音障Sonic boom 音爆Sound speed 音速Soundwich 消音蜂窝夹层结构Source 源Space shuttle 航天飞机Spar 翼梁Spar-wing 梁式机翼Specific heat 比热Specific heat ratio 比热比Speed brake 减速板Speed coefficient 速度系数Speed for maximum endurance 最经济速度Speed for maximum range 最大航程速度Speed range 速度范围Spin 尾旋Spin wind tunnel 尾旋风洞Spiral 盘旋升降Spiral mode 螺旋模态Split aileron 分裂式副翼Spoiler 扰流片Sporting airplane 体育机Spray resistance 滑行阻力Spring tab 弹簧补偿片Stability 稳定性Stability augmentation system 增稳系统Stability axis 稳定性坐标系Stability coefficient 稳定系数Stability wind tunnel 稳定性风洞Stability(seaplane) 安定性（水上飞机）Stabilizer 水平安定面Stagnation line 驻线Stagnation point 驻点Stall 失速Stall angle 失速迎角Stall without power 无动力失速Stalling speed 失速速度Standard atmosphere 标准大气压Starting load 启动载荷Static derivative 静导数Static pressure 静压Static stability 静稳定性Static temperature 静温Static test 静力试验Steady flight 定常飞行Steady flow 定常流Steady turn 定常盘旋Steep climbing turn 战斗转弯Stick force per g 每g驾驶力Stick-fixed 握杆Stick-free 松杆Straight and level flight 水平直线飞行Strain 应变Stain-gauge balance 应变式天平Strake 边条Strake-wing 边条翼Strategic bombing mission 战略轰炸任务Stream function 流函数Stream line 流线Stream tube 流管Streamline curvature effect 流线弯曲效应Stress 应力Stress concentration 应力集中Stress intensity factor 应力强度因子Stringer 桁条Strip of artificial roughness 粗糙带Structural design limits 结构设计极限Subsonic barrier 音障Subsonic flow 亚音速流Subsonic leading-edge 亚音速前缘Subsonic trailing-edge 亚音速后缘Subsonic wind tunnel 亚音速风洞Suction flap 吸气襟翼Supercritical airfoil 超临界翼型Supersonic airfoil profile 超音速翼型Supersonic flow 超音速流Supersonic leading-edge 超音速前缘Supersonic propeller 超音速桨Supersonic trailing-edge 超音速后缘Supersonic wind tunnel 超音速风洞Support interference correction 支架干扰校正Surface effect take-off and landing system 气垫式起落架Survivability 生存能力Sweep-back angle 后掠角Sweepback wing 后掠翼System 系统T-tail T型尾翼Tab 补偿片Tail 尾翼Tail fairing 机尾罩Tail skid 尾撬机尾座护座Tail unit 尾翼Tailless aircraft 无尾飞机Tailless configuration 无尾布局Tailplane 水平安定面Tailwheel landing gear 后三点式起落架Take-off 起飞Take-off distance 起飞距离Take-off gross weight 起飞总重Take-off power 起飞功率Take-off speed 起飞速度Take-off thrust 起飞推力Take-off weight 起飞重量Tandem propeller 纵串桨Tandem twin rotor helicopter 纵列式双旋翼直升机T anker aircraft 空中加油机Taper ratio 根梢比。

F1 空气动力学Aerodynamics

F1 空气动力学Aerodynamics

AerodynamicsA modern Formula One car has almost as much in common with a jet fighter as it does with an ordinary road car. Aerodynamics have become key to success in the sport and teams spend tens of millions of dollars on research and development in the field each year.The aerodynamic designer has two primary concerns: the creation of downforce, to help push the car's tyres onto the track and improve cornering forces; and minimising the drag that gets caused by turbulence and acts to slow the car down.Several teams started to experiment with the now familiar wings in the late 1960s. Race car wings operate on exactly the same principle as aircraft wings, only in reverse. Air flows at different speeds over the two sides of the wing (by having to travel different distances over its contours) and this creates a difference in pressure, a physical rule known as Bernoulli's Principle. As this pressure tries to balance, the wing tries to move in the direction of the low pressure. Planes use their wings to create lift, race cars use theirs to create downforce. A modern Formula One car is capable of developing 3.5 g lateral cornering force (three and a half times its own weight) thanks to aerodynamic downforce. That means that, theoretically, at high speeds they could drive upside down.Early experiments with movable wings and high mountings led to some spectacular accidents, and for the 1970 season regulations were introduced to limit the size and location of wings. Evolved over time, those rules still hold largely true today.By the mid 1970s 'ground effect' downforce had been discovered. Lotus engineers found out that the entire car could be made to actlike a wing by the creation of a giant wing onits underside which would help to suck it to theroad. The ultimate example of this thinkingwas the Brabham BT46B, designed by GordonMurray, which actually used a cooling fan to extract air from the skirted area under the car,creating enormous downforce. After technical challenges from other teams it was withdrawnafter a single race. And rule changes followed to limit the benefits of 'ground effects' - firstly aban on the skirts used to contain the lowpressure area, later a requirement for a'stepped floor'.Despite the full-sized wind tunnels and vast computing power used by the aerodynamic departments of most teams, the fundamental principles of Formula One aerodynamics still apply: to create the maximum amount ofdownforce for the minimal amount of drag.The primary wings mounted front and rear are fitted with different profiles depending on thedownforce requirements of a particular track.Tight, slow circuits like Monaco require veryaggressive wing profiles - you will see thatcars run two separate 'blades' of 'elements' onthe rear wings (two is the maximumpermitted). In contrast, high-speed circuits likeMonza see the cars stripped of as much wingas possible, to reduce drag and increasespeed on the long straights.Every single surface of a modern FormulaOne car, from the shape of the suspensionlinks to that of the driver's helmet - has itsaerodynamic effects considered. Disrupted air,where the flow 'separates' from the body,creates turbulence which creates drag - whichslows the car down. Look at a recent car andyou will see that almost as much effort hasbeen spent reducing drag as increasingdownforce - from the vertical end-plates fittedto wings to prevent vortices forming to thediffuser plates mounted low at the back, whichhelp to re-equalise pressure of the faster-flowing air that has passed under the car andwould otherwise create a low-pressure'balloon' dragging at the back. Despite this, designers can't make their cars too 'slippery', as a good supply of airflow has to be ensured to help dissipate the vast amounts of heat produced by a modern Formula One engine. In recent years most Formula One teams have tried to emulate Ferrari's 'narrow waist' design, where the rear of the car is made as narrow and low as possible. This reduces drag and maximises the amount of air available to the rear wing. The 'barge boards' fitted to the sides of cars also helped to shape the flow of the air and minimise the amount of turbulence. Revised regulations introduced in 2005 forced the aerodynamicists to be even more ingenious. In a bid to cut speeds, the FIA robbed the cars of a chunk of downforce by raising the front wing, bringing the rear wing forward and modifying the rear diffuser profile. The designers quickly clawed back much of the loss, with a variety of intricate and novel solutions such as the ‘horn’ winglets first seen on the McLaren MP4-20.Most of those innovations have been effectively outlawed under the even more stringent aerodynamic regulations imposed by the FIA for 2009. The changes are designed to promote overtaking by making it easier for a car to closely follow another. The new rules take the cars into another new era, with lower and wider front wings, taller and narrower rear wings, and generally much ‘cleaner’ bodywork. Perhaps the most interesting change, however, is the introduction of ‘moveable aerodynamics’, with the driver now able to make limited adjustments to the front wing from the cockpit during a race.All this will make the cars slower initially, but as ever Formula One’s best brains will be working flat out to make up the performance shortfall as quickly as possible.。