Simulated And Experimental Investigation On The Aerodynamic Noise Of High-speed Train

Nowadays,with the rapid increase of train speed,aerodynamic noise has increased dramatically,which has become the biggest noise of the high speed train.Excessive noise will pollute the environment,it not only decreases the comfort level of passengers,but also disturbs normal life of the resident nearby railway.Therefore,high-speed train noise issue has become an important topic to solve in high-speed train development process.In this paper,starting from the study of the theory of high-speed train aerodynamic noise,combined with online experiment,the simulation of aerodynamic noise and control method were studied,mainly including the following parts:(1)Complete the study of the theory of the far field aerodynamic noise of high-speed train,mainly including:State the formation and propagation mechanism of sound wave,then starting from the basic theory of fluid motion,combined with the feature of moving object,the theoretical prediction formula of far field high-speed train aerodynamic noise was established in limited space.They show that dipole source was the main source of aerodynamic noise outside high-speed train which was caused by surface fluctuating pressure,and the aerodynamic noise sound power had a direct ratio of six times with the train speed.(2)On-line experiment was done.Mainly including:Through an own testbed,the aerodynamic noise of high-speed train has been collected nearby viaduct.Some groups of noise were collected when there was no passing-train to eliminate the interference of background noise.Based on these data,spectrum analysis was done.(3)Complete the study of train head simulation and improvement.Mainly including:The full sizes 3d model of train head was created and the fluid simulation model was developed.The external steady flow field was computed by Realizable k-ε turbulence model,and the external transient flow field were calculated by large eddy simulation(LES).Aerodynamic noise sources on the train surface,fluctuating pressure of train surface and the far-field aerodynamic noise were calculated.The results showed that aerodynamic noise of high-speed train is a broad band noise in a wide-band frequency,having no significant main frequency,and test results and simulation results were in good agreement.Based on the results of simulation,the influence of streamlined train head was studied,9 different streamlined train head was created to do the simulation calculation.Then the optimal model was gotten.(4)Complete the study of the whole train simulation.Mainly including:The full sizes 3d model of the whole train was created and the fluid simulation model was developed.The results showed that big train surface pressure is mainly on the train head,bogie,pantograph,the train rear,and small pressure is mainly in the middle of the train and there is little change in the length direction.And the results were in much better agreement than the results of train head.This research is significant to the study and control of the aerodynamic noise of high-speed train.