U型轨高对超导磁浮列车明线运行的气动性能影响OA

To investigate the influence of U-shaped rail height(0,1.5 and 3 m)on the aerodynamic performance of superconducting electrodynamic suspension(EDS)maglev vehicles operating in open air,numerical simulations were conducted using a 1∶25 scaled two-car formation model.The improved delayed detached eddy simulation(IDDES)method was adopted as the turbulence model,which is based on the SST k-ω framework.The flow field characteristics around both the train and the track structure were analyzed,and the accuracy of the numerical methodology was validated through wind tunnel experiments.The results show that as the U-shaped rail height increases from 0 m to 1.5 m,the drag coefficients of the head and tail cars increase significantly by 40%and 24.6%,respectively,while the lift characteristics change from a negative-positive configuration to a positive-negative configuration.When the U-shaped rail height is further increased to 3 m,the drag of the head car decreases,whereas its lift coefficients decreases sharply by 73.7%.With increasing U-shaped rail height,the negative pressure in the streamlined region of the train roof progressively intensifies,while pressure fluctuations near the roof windshield gradually attenuate.In contrast,pressure pulsations along both sides and the underside of the train body increase markedly.The vortex cores move away from the train surface in both the spanwise and vertical directions and gradually detach from the car body,accompanied by a reduction in turbulent kinetic energy in the flow field around the train.Additionally,as the airflow develops downstream,the wake velocity gradually decreases,with the minimum wake velocity occurring at a U-shaped rail height of 3 m.This indicates that higher U-shaped side rails inhibit the formation of low-speed vortices,resulting in a more uniform wake velocity distribution.