The dynamic performance of high-speed trains is significantly influenced by sudden changes in aerodynamic loads(ADLs)when exiting a tunnel in a windy environment.Focusing on a double-track tunnel under construction in...The dynamic performance of high-speed trains is significantly influenced by sudden changes in aerodynamic loads(ADLs)when exiting a tunnel in a windy environment.Focusing on a double-track tunnel under construction in a mountain railway,we established an aerodynamic model involving a train exiting the tunnel,and verified it in the Fluent environment.Overset mesh technology was adopted to characterize the train’s movement.The flow field involving the train,tunnel,and crosswinds was simulated using the Reynolds-averaged turbulence model.Then,we built a comprehensive train-track coupled dynamic model considering the influences of ADLs,to investigate the vehicles’dynamic responses.The aerodynamics and dynamic behaviors of the train when affected by crosswinds with different velocities and directions are analyzed and discussed.The results show that the near-wall side crosswind leads to sharper variations in ADLs than the far-wall side crosswind.The leading vehicle suffers from more severe ADLs than other vehicles,which worsens the wheel-rail interaction and causes low-frequency vibration of the car body.When the crosswind velocity exceeds 20 m/s,significant wheel-rail impacts occur,and the running safety of the train worsens rapidly.展开更多
The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(ID...The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.展开更多
Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China.Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodyna...Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China.Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodynamic assessment,this paper primarily reviews five meaningful progresses on the aerodynamics of the train-bridge system done by Wind Tunnel Laboratory of Central South University in the past several years.Firstly,the flow around the train and the uncertainty origin of the aerodynamic assessment are described from the fluid mechanism point of view.After a brief introduction of the current aerodynamic assessment methods with their strengths and weaknesses,a new-developed TRAIN-INFRASTRUCTURE rig with the maximum launch speed of 35 m/s is introduced.Then,several benchmark studies are presented,including the statistic results of the characterized geometry parameters of the currently utilized bridge-decks,the aerodynamics of the train,and the aerodynamics of the flat box/truss bridge-decks.Upon compared with the foregoing mentioned benchmarks,this paper highlights the aerodynamic interference of the train-bridge system associated with its physical natures.Finally,a porosity-and orientation-adjustable novel wind barrier with its effects on the aerodynamics of the train-bridge system is discussed.展开更多
In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measur...In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measurements of two typical sections, one train-head section and one train-body section, at the windward and leeward tracks were conducted under the smooth and turbulence flows with wind attack angles between-6° and 6°, and the corresponding aerodynamic force coefficients were also calculated using the integral method. The experimental results indicate that the track position affects the mean aerodynamic characteristics of the vehicle, especially for the train-body section. The fluctuating pressure coefficients at the leeward track are more significantly affected by the bridge interference compared to those at the windward track. The effect of turbulence on the train-head section is less than that on the train-body section. Additionally, the mean aerodynamic force coefficients are almost negatively correlated to wind attack angles, which is more prominent for vehicles at the leeward track. Moreover, the lateral force plays a critical role in determining the corresponding overturning moment, especially on the train-body section.展开更多
The irregularities on trains bodies are normally ignored or greatly simplified in studies concerned with aerodynamics.However,surface roughness is known to affect the flow characteristics in the boundary layer near th...The irregularities on trains bodies are normally ignored or greatly simplified in studies concerned with aerodynamics.However,surface roughness is known to affect the flow characteristics in the boundary layer near the wall,hence potentially influencing the aerodynamic performance of a train.This work investigates the effects of roughness on the overall aerodynamic characteristics of a high-speed train subjected to crosswinds.Both experimental work and numerical work have been conducted to simulate a typical high-speed train with a 90?yaw angle,with both a smooth and rough surface.Roughness is applied to the roof of the train surface in the form of longitudinal strips.Results reveal that the addition of roughness is able to reduce the surface pressure on the roof and leeside of the train.Numerical results agree well with experimental ones and confirm that an increase in the roughness relative size can effectively restrain flow separation and reduce surface pressure.Moreover,numerical simulation results show that side force coefficient and roll moment coefficient subjected to rough model significantly decreased compared with smooth model.The conclusions drawn in this study offer the chance to derive critical reference values for the optimization of the aerodynamic characteristics of high-speed trains.展开更多
Two trains passing each other is controlling factor for the wind-vehicle-bridge systems.To test the aerodynamic characteristics of moving vehicles under crosswinds when two trains are passing each other,a wind tunnel ...Two trains passing each other is controlling factor for the wind-vehicle-bridge systems.To test the aerodynamic characteristics of moving vehicles under crosswinds when two trains are passing each other,a wind tunnel test device,which has two moving tracks,was developed.The rationality of the test result was discussed,the effects of intersection mode,yaw angle and lane spacing on the aerodynamic coefficients of the leeward train were analyzed,and the difference of aerodynamic coefficients between the head vehicle and the tail vehicle was discussed.The results show that the proposed test device has good repeatability.The intersection modes have a certain effect on the aerodynamic force of the leeward train when two trains are passing each other,and the results should be more reasonable during the two trains dynamic passing each other.With the decrease of yaw angle,the sudden change of train aerodynamic coefficients is more obvious.The decrease of lane spacing will increase the sudden change of leeward vehicles.In the process of two trains passing each other,the aerodynamic coefficients of the head vehicle and tail vehicle are significantly different,so the coupling vibration analysis of wind-vehicle-bridge system should be considered separately.展开更多
Detached eddy simulation has been widely applied to simulate the flow around trains in recent years.The Reynolds-averaged Navier-Stokes(RANS)model for delayed detached eddy simulation(DDES)is an essential user input.T...Detached eddy simulation has been widely applied to simulate the flow around trains in recent years.The Reynolds-averaged Navier-Stokes(RANS)model for delayed detached eddy simulation(DDES)is an essential user input.The effect of the RANS model for DDES on the aerodynamic characteristics of a train in crosswinds is investigated in this study.Three different DDES models are used,based on the Spalart-Allmaras model(SA),the realizable k-εmodel(RKE),and the shear stress transport k-ωmodel(SST).Results show that all DDES models can give relatively accurate predictions of pressure coefficient on almost all surfaces.There are only some specific differences in the small vortices,while similar flow patterns around trains could be predicted.The SST based DDES model(SSTDDES)gives the most accurate numerical results among the three models for the surface pressure.The variations in pressure on the leeward face play a key role in the variation of the side force.展开更多
Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate ...Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate urban traffic congestion due to its independent right-of-way and minimal ground footprint.However,the SMS possesses a special traveling system with unique vehicle structure and bridge configuration,which results in significant differences in both the mechanisms and dynamics problems associated with train–bridge interaction(TBI)when contrasted with those of traditional railway systems.Therefore,a thorough understanding of the SMS dynamics is essential for ensuring the operational safety of the system.This article presents a state-of-the-art review of the TBI modeling methodologies,critical dynamic features,field tests,and practice of the SMS in China.Firstly,the development history,technical features,and potential dynamics problems of the SMS are briefly described,followed by the mechanical characteristics and mechanisms of the train–bridge interactive systems.Then,the modeling methodology of the fundamental elements in the suspended monorail TBI is systematically reviewed,including the suspended train subsystem,bridge subsystem,train–bridge interaction relationships,system excitations,and solution method.Further,the typical dynamic features of the TBI under various operational scenarios are elaborated,including different train speeds,a variety of line sections,and a natural wind environment.Finally,the first new energy-based SMS test line in the world is systematically introduced,including the composition and functionality of the system,the details of the conducted field tests,and the measured results of the typical dynamic responses.At the end of the paper,both the guidance on further improvement of the SMS and future research topics are proposed.展开更多
Currently,the design of high-temperature superconducting(HTS)maglev trains adopts a U-shaped track operation mode,and the height of the side track significantly impacts the train’s aerodynamic characteristics.In this...Currently,the design of high-temperature superconducting(HTS)maglev trains adopts a U-shaped track operation mode,and the height of the side track significantly impacts the train’s aerodynamic characteristics.In this study,we used computational fluid dynamics(CFD)methods,based on the 3D Reynolds-averaged Navier-Stokes(RANS)method and shear stress transport(SST)k-ωturbulence model,to deeply investigate the effects of the presence or absence of a U-shaped track and different side track heights(800,880,and 960 mm)on the pressure distribution,velocity distribution,and flow field structure of HTS maglev trains at a speed of 400 km/h under crosswinds.The numerical methods were verified using a scaled ICE-2 model wind tunnel test.First,the aerodynamic characteristics of the train under different wind direction angles with and without side tracks were studied.We found that the aerodynamic performance of the train is the most adverse when the wind direction angle is 90°.The presence of a U-shaped track can effectively reduce the lateral force,lift,and yawing moment of the train.The aerodynamic performance of the first suspension bogie at the bottom,which is the worst,will also be effectively improved.Next,the aerodynamic effects of different side track heights on the HTS maglev train were studied.An increase in side track height will reduce the lift and lateral force of the train,while the increase in drag is relatively small.Under the premise of ensuring passengers can conveniently alight,we found that a U-shaped track with a side track height of 960 mm has the best aerodynamic performance.The research findings offer a valuable reference for the engineering application and design of the track structure of HTS maglev train systems.展开更多
Irregularities in the track and uneven forces acting on the train can cause shifts in the position of the superconducting magnetic levitation train relative to the track during operation.These shifts lead to asymmetri...Irregularities in the track and uneven forces acting on the train can cause shifts in the position of the superconducting magnetic levitation train relative to the track during operation.These shifts lead to asymmetries in the flow field structure on both sides of the narrow suspension gap,resulting in instability and deterioration of the train’s aerodynamic characteristics,significantly impacting its operational safety.In this study,we firstly validate the aerodynamic characteristics of the superconducting magnetic levitation system by developing a numerical simulation method based on wind tunnel test results.We then investigate the influence of lateral translation parameters on the train’s aerodynamic performance under conditions both with and without crosswinds.We aim to clarify the evolution mechanism of the flow field characteristics under the coupling effect between the train and the U-shaped track and to identify the most unfavorable operational parameters contributing to the deterioration of the train’s aerodynamic properties.The findings show that,without crosswinds,a lateral translation of 30 mm causes a synchronous resonance phenomenon at the side and bottom gaps of the train-track coupling,leading to the worst aerodynamic performance.Under crosswind conditions,a lateral translation of 40 mm maximizes peak pressure fluctuations and average turbulent kinetic energy around the train,resulting in the poorest aerodynamic performance.This research provides theoretical support for enhancing the operational stability of superconducting magnetic levitation trains.展开更多
In view of the situation of multi-temperature,multi-medium and multi-discharge equipment on the integrated exhaust end platform of a natural gas distributed energy station,which is compact in layout,mutual influence,c...In view of the situation of multi-temperature,multi-medium and multi-discharge equipment on the integrated exhaust end platform of a natural gas distributed energy station,which is compact in layout,mutual influence,complex aerodynamic field and complex heat and mass transfer field,the temperature field and aerodynamic field of the platform were comprehensively studied through field experiments and numerical simulation.The research results show that the high temperature flue gas discharged from the chimney is hindered by the chimney cap and returns downward.The noise reduction walls around the chimney make the top of the platform pressurized under the crosswind,as a result,the inlet air temperature of each cooling equipment is generally higher than the ambient temperature,and the cooling efficiency is extremely low.According to the numerical simulation results,the effect of hot gas recirculation is intensified by the ambient crosswind.With the increase of the ambient crosswind,the flue gases coverage expands.The influence of ambient crosswind on inlet air temperature first increases and then decreases within the range of 1–8 m/s,showing a nearly normal distribution.Secondly,this study innovatively designed a new V-shaped chimney cap,compared with the A-shaped chimney cap,the new chimney cap effectively reduces its own obstruction to the smoke and changes the flow path of the smoke.After the smoke rises for a certain distance,the smoke returns downward,which effectively reduces the temperature of the smoke and thus reduces its impact on the air inlet of the cooling equipment.On-site measurement found that the cooling efficiency of various cooling equipment has increased by an average of 27.3%compared to before the renovation,and centrifuge’s refrigeration capacity increased by 0.78 GJ/h.展开更多
The share of freight transportation is increasing on Wyoming’s roads. These roads are characterized by challenging mountainous terrain and severe crosswinds. The stability of freight trucks in such conditions is of g...The share of freight transportation is increasing on Wyoming’s roads. These roads are characterized by challenging mountainous terrain and severe crosswinds. The stability of freight trucks in such conditions is of great concern to transportation agencies. Therefore, high-fidelity vehicle dynamics simulation modeling was implemented to investigate the rollover propensity of trucks navigating curves. Scenarios included various road geometric designs, truck characteristics and wind conditions. A multiple linear regression model was also developed to investigate the impact of key parameters on truck rollover propensity. The modeling results indicated that wind speed and direction were influential factors in terms of truck roll stability. Trucks had a 76% higher chance of rolling over when subjected to 40 mph winds relative to being subjected to 20 mph winds assuming all else was unchanged. This study also demonstrated that the most unfavorable wind direction was not perpendicular (90 degrees) to the truck since the truck would continuously change its orientation when traversing combined horizontal and vertical curves. Its speed would also constantly fluctuate. On the contrary, this study’s results indicated that the 120-degree wind direction was the most critical one. Also, under blowing lateral wind conditions, the gross weight of the truck was found to be a contributing factor to rollover risk. Its impact varied depending on the radius of the horizontal curve the truck was navigating. This critical interaction was ignored in the road safety literature. This study offered new insights about the impacts of truck rollover precursors and, hence, this would lead to the proposition of effective truck safety countermeasures.展开更多
The aerodynamic noise of high-speed trains increases significantly under crosswinds.Researches have typically focused on the characteristics of aerodynamic loads and the corresponding safety issues,with less attention...The aerodynamic noise of high-speed trains increases significantly under crosswinds.Researches have typically focused on the characteristics of aerodynamic loads and the corresponding safety issues,with less attention to flow-induced noise characteristics.In the present paper,the near-field unsteady flow behaviour around a pantograph was analysed using a large eddy simulation.The far-field aerodynamic noise from a pantograph was predicted using the Ffowcs Williams-Hawkings acoustic analogy.The results showed that asymmetric characteristics of the flow field could be observed using the turbulent kinetic energy and the instantaneous vortexes in crosswind conditions.Vortex shedding,flow separation and recombination around the pantograph were the key factors for aerodynamic noise generation.The directivity of the noise radiation was inclined towards the leeward side of the pantograph.The aerodynamic noise propagation pattern can be considered as a typical point source on spherical waves when the transverse distance from the pantograph geometrical centre is farther than 8 m.The sound pressure level grew approximately as the 6 th power of the pantograph speed.The peak frequency exhibited a linear relationship with the crosswind velocity.The numerical simulation results and wind tunnel experiments had high consistency in the full frequency domain,namely,the peak frequency distribution range,the main frequency amplitude and the spectral distribution shape.展开更多
The large number and dense layout of rail fastening can significantly affect the aerodynamic performance of trains.Utilizing the Improved Delayed Detached Eddy Simulation(IDDES)approach based on the SST(Shear Stress T...The large number and dense layout of rail fastening can significantly affect the aerodynamic performance of trains.Utilizing the Improved Delayed Detached Eddy Simulation(IDDES)approach based on the SST(Shear Stress Transport)k-ωturbulent model,this study evaluates the effects of the rail fastening system on the aerodynamic force,slipstream and train wake under crosswind conditions.The results indicate that in such conditions,compared to the model without rails,the rail and the fastening system reduce the drag force coefficient of the train by 1.69%,while the lateral force coefficients increase by 1.16%and 0.87%,respectively.The aerodynamic force can be considered virtually unchanged within the error allowance.However,the rail and the fastening system cause an inward shift of the negative pressure center on the leeward side of the train.The peak slipstream velocity near the ground in the rail and rail fastening system model is significantly lower than that in the situation without rails.Additionally,the rail and the fastening system not only induce two displacements in the vortex structure of the train but also accelerate the dissipation of shedding vortex and the rapid decrease of turbulent kinetic energy.展开更多
In this study,the unsteady Reynolds-averaged Navier–Stokes algorithm coupled with the Discrete Phase Model(DPM)was used to study the accumulation of snow in the bogie region of a high-speed train under crosswind cond...In this study,the unsteady Reynolds-averaged Navier–Stokes algorithm coupled with the Discrete Phase Model(DPM)was used to study the accumulation of snow in the bogie region of a high-speed train under crosswind conditions.Moreover,the impact of active blowing schemes on the airflow around the bogie and the dynamics and deposition of snow particles were also assessed.According to the results:in the crosswind environment,active blowing changes the flow field in the bogie area,reducing the flow of air coming from the windward side and bottom of the bogie.The trajectory of snow particles carried by crosswinds is modified due to the reduced airflow into the bogie region.With no active blowing,snow accumulation is mainly concentrated in the bogie cavity,frame,and primary suspension;while it is reduced by nearly an order of magnitude as soon as blowing is enabled.Blowing speeds need to be distributed appropriately in order to achieve the best possible snow protection.Continuously increasing the blowing speed on one side does not improve the amount of snow in the bogie region.The optimal condition for snow prevention of the entire train is achieved with a windward side blowing speed of 4 m/s and a leeward side blowing speed of 6 m/s,resulting in a snow reduction rate of 95.6%.Moreover,higher blowing speeds on the leeward side are beneficial for mitigating snow accumulation in the bogie region.展开更多
Purpose-Express freight transportation is in rapid development currently.Owing to the higher speed of express freight train,the deformation of the bridge deck worsens the railway line condition under the action of win...Purpose-Express freight transportation is in rapid development currently.Owing to the higher speed of express freight train,the deformation of the bridge deck worsens the railway line condition under the action of wind and train moving load when the train runs over a long-span bridge.Besides,the blunt car body of vehicle has poor aerodynamic characteristics,bringing a greater challenge on the running stability in the crosswind.Design/methodology/approach-In this study,the aerodynamic force coefficients of express freight vehicles on the bridge are measured by scale model wind tunnel test.The dynamic model of the train-long-span steel truss bridge coupling system is established,and the dynamic response as well as the running safety of vehicle are evaluated.Findings-The results show that wind speed has a significant influence on running safety,which is mainly reflected in the over-limitation of wheel unloading rate.The wind speed limit decreases with train speed,and it reduces to 18.83 m/s when the train speed is 160 km/h.Originality/value-This study deepens the theoretical understanding of the interaction between vehicles and bridges and proposes new methods for analyzing similar engineering problems.It also provides a new theoretical basis for the safety assessment of express freight trains.展开更多
This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state an...This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.展开更多
The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years.The objective of the present paper was to investigate the aerodynamic ch...The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years.The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach.An aerodynamic model of a high-speed train was first set up,and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach.Then,the effects of the yaw angle,the resultant wind speed,and the rainfall rate on aerodynamic coefficients were analyzed.The results indicate that the aerodynamic coefficients grow almost linearly with the rainfall rate,and increase with a decrease in the resultant wind speed.Due to the impact of raindrops on the train surface and the airflow,the pressure coefficients of windward and leeward side of the train become larger with the increase of the rainfall rate.Raindrops can accelerate the airflow and suppress the vortices detachment.Moreover,the flow velocity in regions surrounding the train increases with an increase in the rainfall rate.展开更多
Nonlinear amphibious vehicle rolling under regular waves and wind load is analyzed by a single degree of freedom system.Considering nonlinear damping and restoring moments,a nonlinear rolling dynamical equation of amp...Nonlinear amphibious vehicle rolling under regular waves and wind load is analyzed by a single degree of freedom system.Considering nonlinear damping and restoring moments,a nonlinear rolling dynamical equation of amphibious vehicle is established.The Hamiltonian function of the nonlinear rolling dynamical equation of amphibious vehicle indicate when subjected to joint action of periodic wave excitation and crosswind,the nonlinear rolling system degenerates into being asymmetric.The threshold value of excited moment of wave and wind is analyzed by the Melnikov method.Finally,the nonlinear rolling motion response and phase portrait were simulated by four order Runge-Kutta method at different excited moment parameters.展开更多
The numerical simulation based on Reynolds time-averaged equation is one of the approved methods to evaluate the aerodynamic performance of trains in crosswind.However,there are several turbulence models,trains may pr...The numerical simulation based on Reynolds time-averaged equation is one of the approved methods to evaluate the aerodynamic performance of trains in crosswind.However,there are several turbulence models,trains may present different aerodynamic performances in crosswind using different turbulence models.In order to select the most suitable turbulence model,the inter-city express 2(ICE2)model is chosen as a research object,6 different turbulence models are used to simulate the flow characteristics,surface pressure and aerodynamic forces of the train in crosswind,respectively.6 turbulence models are the standard k-ε,Renormalization Group(RNG)k-ε,Realizable k-ε,Shear Stress Transport(SST)k-ω,standard k-ωand Spalart-Allmaras(SPA),respectively.The numerical results and the wind tunnel experimental data are compared.The results show that the most accurate model for predicting the surface pressure of the train is SST k-ω,followed by Realizable k-ε.Compared with the experimental result,the error of the side force coefficient obtained by SST k-ωand Realizable k-εturbulence model is less than 1%.The most accurate prediction for the lift force coefficient is achieved by SST k-ω,followed by RNG k-ε.By comparing 6 different turbulence models,the SST k-ωmodel is most suitable for the numerical simulation of the aerodynamic behavior of trains in crosswind.展开更多
基金National Natural Science Foundation of China(No.52388102)New Cornerstone Science Foundation through the Xplorer Prize.
文摘The dynamic performance of high-speed trains is significantly influenced by sudden changes in aerodynamic loads(ADLs)when exiting a tunnel in a windy environment.Focusing on a double-track tunnel under construction in a mountain railway,we established an aerodynamic model involving a train exiting the tunnel,and verified it in the Fluent environment.Overset mesh technology was adopted to characterize the train’s movement.The flow field involving the train,tunnel,and crosswinds was simulated using the Reynolds-averaged turbulence model.Then,we built a comprehensive train-track coupled dynamic model considering the influences of ADLs,to investigate the vehicles’dynamic responses.The aerodynamics and dynamic behaviors of the train when affected by crosswinds with different velocities and directions are analyzed and discussed.The results show that the near-wall side crosswind leads to sharper variations in ADLs than the far-wall side crosswind.The leading vehicle suffers from more severe ADLs than other vehicles,which worsens the wheel-rail interaction and causes low-frequency vibration of the car body.When the crosswind velocity exceeds 20 m/s,significant wheel-rail impacts occur,and the running safety of the train worsens rapidly.
基金supported by Wuyi University Hong Kong and Macao Joint Research and Development Fund(GrantsNos.2021WGALH15,2019WGALH17,2019WGALH15)the National Natural Science Foundation of China-Guangdong Joint Fund(GrantsNo.2019A1515111052)+2 种基金the National Natural Science Foundation of China(Grant No.52202426)a grant from the Research Grants Council(RGC)of the Hong Kong Special Administrative Region(SAR),China(Grants No.15205723)a grant from the Hong Kong Polytechnic University(Grant No.P0045325).
文摘The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.
基金Project(2017YFB1201204)supported by National Key R&D Program of ChinaProjects(51925808,U1934209)supported by the National Natural Science Foundation of China。
文摘Serviceability and running safety of the high-speed train on/through a bridge are of major concern in China.Due to the uncertainty chain of the train dynamic analysis in crosswinds originating mainly from the aerodynamic assessment,this paper primarily reviews five meaningful progresses on the aerodynamics of the train-bridge system done by Wind Tunnel Laboratory of Central South University in the past several years.Firstly,the flow around the train and the uncertainty origin of the aerodynamic assessment are described from the fluid mechanism point of view.After a brief introduction of the current aerodynamic assessment methods with their strengths and weaknesses,a new-developed TRAIN-INFRASTRUCTURE rig with the maximum launch speed of 35 m/s is introduced.Then,several benchmark studies are presented,including the statistic results of the characterized geometry parameters of the currently utilized bridge-decks,the aerodynamics of the train,and the aerodynamics of the flat box/truss bridge-decks.Upon compared with the foregoing mentioned benchmarks,this paper highlights the aerodynamic interference of the train-bridge system associated with its physical natures.Finally,a porosity-and orientation-adjustable novel wind barrier with its effects on the aerodynamics of the train-bridge system is discussed.
基金Projects(51808563,51925808)supported by the National Natural Science Foundation of ChinaProject(KLWRTBMC18-03)supported by the Open Research Fund of the Key Laboratory of Wind Resistance Technology of Bridges of ChinaProject(2017YFB1201204)supported by the National Key R&D Program of China。
文摘In this study, experiments were carried out to investigate aerodynamic characteristics of a high-speed train on viaducts in turbulent crosswinds using a 1:25 scaled sectional model wind-tunnel testing. Pressure measurements of two typical sections, one train-head section and one train-body section, at the windward and leeward tracks were conducted under the smooth and turbulence flows with wind attack angles between-6° and 6°, and the corresponding aerodynamic force coefficients were also calculated using the integral method. The experimental results indicate that the track position affects the mean aerodynamic characteristics of the vehicle, especially for the train-body section. The fluctuating pressure coefficients at the leeward track are more significantly affected by the bridge interference compared to those at the windward track. The effect of turbulence on the train-head section is less than that on the train-body section. Additionally, the mean aerodynamic force coefficients are almost negatively correlated to wind attack angles, which is more prominent for vehicles at the leeward track. Moreover, the lateral force plays a critical role in determining the corresponding overturning moment, especially on the train-body section.
基金The work was financed by the program of China Scholarships Council,Youth Innovation Promotion Association CAS(2019020)a University of Birmingham(UK)funded scholarship and was supported by the EU H2O2O project LiftTRAIN(701693)。
文摘The irregularities on trains bodies are normally ignored or greatly simplified in studies concerned with aerodynamics.However,surface roughness is known to affect the flow characteristics in the boundary layer near the wall,hence potentially influencing the aerodynamic performance of a train.This work investigates the effects of roughness on the overall aerodynamic characteristics of a high-speed train subjected to crosswinds.Both experimental work and numerical work have been conducted to simulate a typical high-speed train with a 90?yaw angle,with both a smooth and rough surface.Roughness is applied to the roof of the train surface in the form of longitudinal strips.Results reveal that the addition of roughness is able to reduce the surface pressure on the roof and leeside of the train.Numerical results agree well with experimental ones and confirm that an increase in the roughness relative size can effectively restrain flow separation and reduce surface pressure.Moreover,numerical simulation results show that side force coefficient and roll moment coefficient subjected to rough model significantly decreased compared with smooth model.The conclusions drawn in this study offer the chance to derive critical reference values for the optimization of the aerodynamic characteristics of high-speed trains.
基金Projects(51778544,51978589,51908472) supported by the National Natural Science Foundation of ChinaProject(2682021CG014) supported by the Fundamental Research Funds for the Central Universities,China。
文摘Two trains passing each other is controlling factor for the wind-vehicle-bridge systems.To test the aerodynamic characteristics of moving vehicles under crosswinds when two trains are passing each other,a wind tunnel test device,which has two moving tracks,was developed.The rationality of the test result was discussed,the effects of intersection mode,yaw angle and lane spacing on the aerodynamic coefficients of the leeward train were analyzed,and the difference of aerodynamic coefficients between the head vehicle and the tail vehicle was discussed.The results show that the proposed test device has good repeatability.The intersection modes have a certain effect on the aerodynamic force of the leeward train when two trains are passing each other,and the results should be more reasonable during the two trains dynamic passing each other.With the decrease of yaw angle,the sudden change of train aerodynamic coefficients is more obvious.The decrease of lane spacing will increase the sudden change of leeward vehicles.In the process of two trains passing each other,the aerodynamic coefficients of the head vehicle and tail vehicle are significantly different,so the coupling vibration analysis of wind-vehicle-bridge system should be considered separately.
基金the National Natural Science Foundation of China(No.51605397)Sichuan Science and Technology Program(No.2019YJ0227)+1 种基金China Postdoctoral Science Foundation(No.2019M663550)Self-determined Project of State Key Laboratory of Traction Power(2019TPL_T02).
文摘Detached eddy simulation has been widely applied to simulate the flow around trains in recent years.The Reynolds-averaged Navier-Stokes(RANS)model for delayed detached eddy simulation(DDES)is an essential user input.The effect of the RANS model for DDES on the aerodynamic characteristics of a train in crosswinds is investigated in this study.Three different DDES models are used,based on the Spalart-Allmaras model(SA),the realizable k-εmodel(RKE),and the shear stress transport k-ωmodel(SST).Results show that all DDES models can give relatively accurate predictions of pressure coefficient on almost all surfaces.There are only some specific differences in the small vortices,while similar flow patterns around trains could be predicted.The SST based DDES model(SSTDDES)gives the most accurate numerical results among the three models for the surface pressure.The variations in pressure on the leeward face play a key role in the variation of the side force.
基金supported by the National Natural Science Foundation of China(Grant Nos.52202483,52108476,and 52388102)。
文摘Urban transportation systems are facing severe challenges due to the rapid growth of the urban population,especially in China.Suspended monorail system(SMS),as a sky rail transportation form,can effectively alleviate urban traffic congestion due to its independent right-of-way and minimal ground footprint.However,the SMS possesses a special traveling system with unique vehicle structure and bridge configuration,which results in significant differences in both the mechanisms and dynamics problems associated with train–bridge interaction(TBI)when contrasted with those of traditional railway systems.Therefore,a thorough understanding of the SMS dynamics is essential for ensuring the operational safety of the system.This article presents a state-of-the-art review of the TBI modeling methodologies,critical dynamic features,field tests,and practice of the SMS in China.Firstly,the development history,technical features,and potential dynamics problems of the SMS are briefly described,followed by the mechanical characteristics and mechanisms of the train–bridge interactive systems.Then,the modeling methodology of the fundamental elements in the suspended monorail TBI is systematically reviewed,including the suspended train subsystem,bridge subsystem,train–bridge interaction relationships,system excitations,and solution method.Further,the typical dynamic features of the TBI under various operational scenarios are elaborated,including different train speeds,a variety of line sections,and a natural wind environment.Finally,the first new energy-based SMS test line in the world is systematically introduced,including the composition and functionality of the system,the details of the conducted field tests,and the measured results of the typical dynamic responses.At the end of the paper,both the guidance on further improvement of the SMS and future research topics are proposed.
基金supported by the National Natural Science Foundation of China(No.U23A20681)the S&T Program of Hebei Province,China(No.23567602H).
文摘Currently,the design of high-temperature superconducting(HTS)maglev trains adopts a U-shaped track operation mode,and the height of the side track significantly impacts the train’s aerodynamic characteristics.In this study,we used computational fluid dynamics(CFD)methods,based on the 3D Reynolds-averaged Navier-Stokes(RANS)method and shear stress transport(SST)k-ωturbulence model,to deeply investigate the effects of the presence or absence of a U-shaped track and different side track heights(800,880,and 960 mm)on the pressure distribution,velocity distribution,and flow field structure of HTS maglev trains at a speed of 400 km/h under crosswinds.The numerical methods were verified using a scaled ICE-2 model wind tunnel test.First,the aerodynamic characteristics of the train under different wind direction angles with and without side tracks were studied.We found that the aerodynamic performance of the train is the most adverse when the wind direction angle is 90°.The presence of a U-shaped track can effectively reduce the lateral force,lift,and yawing moment of the train.The aerodynamic performance of the first suspension bogie at the bottom,which is the worst,will also be effectively improved.Next,the aerodynamic effects of different side track heights on the HTS maglev train were studied.An increase in side track height will reduce the lift and lateral force of the train,while the increase in drag is relatively small.Under the premise of ensuring passengers can conveniently alight,we found that a U-shaped track with a side track height of 960 mm has the best aerodynamic performance.The research findings offer a valuable reference for the engineering application and design of the track structure of HTS maglev train systems.
基金Projects(52372369,52302447,52388102)supported by the National Natural Science Foundation of ChinaProjects(2022YFB4301201-02,2023YFB4302502-02)supported by the National Key R&D Program of China。
文摘Irregularities in the track and uneven forces acting on the train can cause shifts in the position of the superconducting magnetic levitation train relative to the track during operation.These shifts lead to asymmetries in the flow field structure on both sides of the narrow suspension gap,resulting in instability and deterioration of the train’s aerodynamic characteristics,significantly impacting its operational safety.In this study,we firstly validate the aerodynamic characteristics of the superconducting magnetic levitation system by developing a numerical simulation method based on wind tunnel test results.We then investigate the influence of lateral translation parameters on the train’s aerodynamic performance under conditions both with and without crosswinds.We aim to clarify the evolution mechanism of the flow field characteristics under the coupling effect between the train and the U-shaped track and to identify the most unfavorable operational parameters contributing to the deterioration of the train’s aerodynamic properties.The findings show that,without crosswinds,a lateral translation of 30 mm causes a synchronous resonance phenomenon at the side and bottom gaps of the train-track coupling,leading to the worst aerodynamic performance.Under crosswind conditions,a lateral translation of 40 mm maximizes peak pressure fluctuations and average turbulent kinetic energy around the train,resulting in the poorest aerodynamic performance.This research provides theoretical support for enhancing the operational stability of superconducting magnetic levitation trains.
基金support from the Shandong Provincial Science and Technology SMEs Innovation Capacity Improvement Project(2023TSGC0087)the Shandong Natural Science Foundation(Grant No.ZR2022ME008)China Postdoctoral Science Foundation(2023M732102).
文摘In view of the situation of multi-temperature,multi-medium and multi-discharge equipment on the integrated exhaust end platform of a natural gas distributed energy station,which is compact in layout,mutual influence,complex aerodynamic field and complex heat and mass transfer field,the temperature field and aerodynamic field of the platform were comprehensively studied through field experiments and numerical simulation.The research results show that the high temperature flue gas discharged from the chimney is hindered by the chimney cap and returns downward.The noise reduction walls around the chimney make the top of the platform pressurized under the crosswind,as a result,the inlet air temperature of each cooling equipment is generally higher than the ambient temperature,and the cooling efficiency is extremely low.According to the numerical simulation results,the effect of hot gas recirculation is intensified by the ambient crosswind.With the increase of the ambient crosswind,the flue gases coverage expands.The influence of ambient crosswind on inlet air temperature first increases and then decreases within the range of 1–8 m/s,showing a nearly normal distribution.Secondly,this study innovatively designed a new V-shaped chimney cap,compared with the A-shaped chimney cap,the new chimney cap effectively reduces its own obstruction to the smoke and changes the flow path of the smoke.After the smoke rises for a certain distance,the smoke returns downward,which effectively reduces the temperature of the smoke and thus reduces its impact on the air inlet of the cooling equipment.On-site measurement found that the cooling efficiency of various cooling equipment has increased by an average of 27.3%compared to before the renovation,and centrifuge’s refrigeration capacity increased by 0.78 GJ/h.
文摘The share of freight transportation is increasing on Wyoming’s roads. These roads are characterized by challenging mountainous terrain and severe crosswinds. The stability of freight trucks in such conditions is of great concern to transportation agencies. Therefore, high-fidelity vehicle dynamics simulation modeling was implemented to investigate the rollover propensity of trucks navigating curves. Scenarios included various road geometric designs, truck characteristics and wind conditions. A multiple linear regression model was also developed to investigate the impact of key parameters on truck rollover propensity. The modeling results indicated that wind speed and direction were influential factors in terms of truck roll stability. Trucks had a 76% higher chance of rolling over when subjected to 40 mph winds relative to being subjected to 20 mph winds assuming all else was unchanged. This study also demonstrated that the most unfavorable wind direction was not perpendicular (90 degrees) to the truck since the truck would continuously change its orientation when traversing combined horizontal and vertical curves. Its speed would also constantly fluctuate. On the contrary, this study’s results indicated that the 120-degree wind direction was the most critical one. Also, under blowing lateral wind conditions, the gross weight of the truck was found to be a contributing factor to rollover risk. Its impact varied depending on the radius of the horizontal curve the truck was navigating. This critical interaction was ignored in the road safety literature. This study offered new insights about the impacts of truck rollover precursors and, hence, this would lead to the proposition of effective truck safety countermeasures.
基金supported by the National Key R&D Program of China(Grant No.2016YFE0205200)the High-Speed Railway Basic Research Fund Key Project of China(Grant No.U1234208)+1 种基金the National Natural Science Foundation of China(Grant Nos.11972179,51475394)the China Postdoctoral Science Foundation(Grant No.2019M662201)。
文摘The aerodynamic noise of high-speed trains increases significantly under crosswinds.Researches have typically focused on the characteristics of aerodynamic loads and the corresponding safety issues,with less attention to flow-induced noise characteristics.In the present paper,the near-field unsteady flow behaviour around a pantograph was analysed using a large eddy simulation.The far-field aerodynamic noise from a pantograph was predicted using the Ffowcs Williams-Hawkings acoustic analogy.The results showed that asymmetric characteristics of the flow field could be observed using the turbulent kinetic energy and the instantaneous vortexes in crosswind conditions.Vortex shedding,flow separation and recombination around the pantograph were the key factors for aerodynamic noise generation.The directivity of the noise radiation was inclined towards the leeward side of the pantograph.The aerodynamic noise propagation pattern can be considered as a typical point source on spherical waves when the transverse distance from the pantograph geometrical centre is farther than 8 m.The sound pressure level grew approximately as the 6 th power of the pantograph speed.The peak frequency exhibited a linear relationship with the crosswind velocity.The numerical simulation results and wind tunnel experiments had high consistency in the full frequency domain,namely,the peak frequency distribution range,the main frequency amplitude and the spectral distribution shape.
基金funded by the National Natural Science Foundation of China(Grant No.12172308).
文摘The large number and dense layout of rail fastening can significantly affect the aerodynamic performance of trains.Utilizing the Improved Delayed Detached Eddy Simulation(IDDES)approach based on the SST(Shear Stress Transport)k-ωturbulent model,this study evaluates the effects of the rail fastening system on the aerodynamic force,slipstream and train wake under crosswind conditions.The results indicate that in such conditions,compared to the model without rails,the rail and the fastening system reduce the drag force coefficient of the train by 1.69%,while the lateral force coefficients increase by 1.16%and 0.87%,respectively.The aerodynamic force can be considered virtually unchanged within the error allowance.However,the rail and the fastening system cause an inward shift of the negative pressure center on the leeward side of the train.The peak slipstream velocity near the ground in the rail and rail fastening system model is significantly lower than that in the situation without rails.Additionally,the rail and the fastening system not only induce two displacements in the vortex structure of the train but also accelerate the dissipation of shedding vortex and the rapid decrease of turbulent kinetic energy.
基金funded by the National Natural Science Foundation of China(Grant No.12172308)the Provincial Natural Science Foundation of Hunan(Grant No.2023JJ40260).
文摘In this study,the unsteady Reynolds-averaged Navier–Stokes algorithm coupled with the Discrete Phase Model(DPM)was used to study the accumulation of snow in the bogie region of a high-speed train under crosswind conditions.Moreover,the impact of active blowing schemes on the airflow around the bogie and the dynamics and deposition of snow particles were also assessed.According to the results:in the crosswind environment,active blowing changes the flow field in the bogie area,reducing the flow of air coming from the windward side and bottom of the bogie.The trajectory of snow particles carried by crosswinds is modified due to the reduced airflow into the bogie region.With no active blowing,snow accumulation is mainly concentrated in the bogie cavity,frame,and primary suspension;while it is reduced by nearly an order of magnitude as soon as blowing is enabled.Blowing speeds need to be distributed appropriately in order to achieve the best possible snow protection.Continuously increasing the blowing speed on one side does not improve the amount of snow in the bogie region.The optimal condition for snow prevention of the entire train is achieved with a windward side blowing speed of 4 m/s and a leeward side blowing speed of 6 m/s,resulting in a snow reduction rate of 95.6%.Moreover,higher blowing speeds on the leeward side are beneficial for mitigating snow accumulation in the bogie region.
基金supported by the Research Major Project of China Academy of Railway Sciences Group Co.,Ltd(Grant No.2021YJ270)the China National Railway Group Science and Technology Program(Grant No.N2022T001).
文摘Purpose-Express freight transportation is in rapid development currently.Owing to the higher speed of express freight train,the deformation of the bridge deck worsens the railway line condition under the action of wind and train moving load when the train runs over a long-span bridge.Besides,the blunt car body of vehicle has poor aerodynamic characteristics,bringing a greater challenge on the running stability in the crosswind.Design/methodology/approach-In this study,the aerodynamic force coefficients of express freight vehicles on the bridge are measured by scale model wind tunnel test.The dynamic model of the train-long-span steel truss bridge coupling system is established,and the dynamic response as well as the running safety of vehicle are evaluated.Findings-The results show that wind speed has a significant influence on running safety,which is mainly reflected in the over-limitation of wheel unloading rate.The wind speed limit decreases with train speed,and it reduces to 18.83 m/s when the train speed is 160 km/h.Originality/value-This study deepens the theoretical understanding of the interaction between vehicles and bridges and proposes new methods for analyzing similar engineering problems.It also provides a new theoretical basis for the safety assessment of express freight trains.
基金Key Laboratory of Low-Grade Energy Utilization Technologies and Systems(LLEUTS-2023001)the Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX1470).
文摘This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.
基金supported by the National Natural Science Foundation of China(Grant No.51705267)China Postdoctoral Science Foundation Grant(Grant No.2018M630750)+1 种基金National Natural Science Foundation of China(Grant No.51605397)Natural Science Foundation of Shandong Province,China(Grant No.ZR2014EEP002).
文摘The performances of high-speed trains in the presence of coupling effects with crosswind and rain have attracted great attention in recent years.The objective of the present paper was to investigate the aerodynamic characteristics of a high-speed train under such conditions in the framework of an Eulerian-Lagrangian approach.An aerodynamic model of a high-speed train was first set up,and the side force coefficient obtained from numerical simulation was compared with that provided by wind tunnel experiments to verify the accuracy of the approach.Then,the effects of the yaw angle,the resultant wind speed,and the rainfall rate on aerodynamic coefficients were analyzed.The results indicate that the aerodynamic coefficients grow almost linearly with the rainfall rate,and increase with a decrease in the resultant wind speed.Due to the impact of raindrops on the train surface and the airflow,the pressure coefficients of windward and leeward side of the train become larger with the increase of the rainfall rate.Raindrops can accelerate the airflow and suppress the vortices detachment.Moreover,the flow velocity in regions surrounding the train increases with an increase in the rainfall rate.
基金The Pre-research Project of the General Armament DepartmentThe Science Fund of North University of China(No.20130105)
文摘Nonlinear amphibious vehicle rolling under regular waves and wind load is analyzed by a single degree of freedom system.Considering nonlinear damping and restoring moments,a nonlinear rolling dynamical equation of amphibious vehicle is established.The Hamiltonian function of the nonlinear rolling dynamical equation of amphibious vehicle indicate when subjected to joint action of periodic wave excitation and crosswind,the nonlinear rolling system degenerates into being asymmetric.The threshold value of excited moment of wave and wind is analyzed by the Melnikov method.Finally,the nonlinear rolling motion response and phase portrait were simulated by four order Runge-Kutta method at different excited moment parameters.
基金Supported by National Natural Science Foundation of China(Grant No.51605397)Sichuan Provincial Science and Technology Program of China(Grant No.2019YJ0227)Self-determined Project of State Key Laboratory of Traction Power(Grant No.2019TPL_T02)
文摘The numerical simulation based on Reynolds time-averaged equation is one of the approved methods to evaluate the aerodynamic performance of trains in crosswind.However,there are several turbulence models,trains may present different aerodynamic performances in crosswind using different turbulence models.In order to select the most suitable turbulence model,the inter-city express 2(ICE2)model is chosen as a research object,6 different turbulence models are used to simulate the flow characteristics,surface pressure and aerodynamic forces of the train in crosswind,respectively.6 turbulence models are the standard k-ε,Renormalization Group(RNG)k-ε,Realizable k-ε,Shear Stress Transport(SST)k-ω,standard k-ωand Spalart-Allmaras(SPA),respectively.The numerical results and the wind tunnel experimental data are compared.The results show that the most accurate model for predicting the surface pressure of the train is SST k-ω,followed by Realizable k-ε.Compared with the experimental result,the error of the side force coefficient obtained by SST k-ωand Realizable k-εturbulence model is less than 1%.The most accurate prediction for the lift force coefficient is achieved by SST k-ω,followed by RNG k-ε.By comparing 6 different turbulence models,the SST k-ωmodel is most suitable for the numerical simulation of the aerodynamic behavior of trains in crosswind.
