Flow and sound fields of scaled high-speed trains with different coach numbers running in long tunnel  

作　　者：Qiliang Li Yuqing Sun Menghan Ouyang Zhigang Yang 

机构地区：[1]School of Automotive Studies,Tongji University,Shanghai 201804,China [2]Shanghai Automotive Wind Tunnel Center,Tongji University,Shanghai 201804,China [3]School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China

出　　处：《Railway Engineering Science》2024年第3期401-420,共20页铁道工程科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 52072267);Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems (Grant No. 23DZ2229029)

摘　　要：Segregated incompressible large eddy simulation and acoustic perturbation equations were used to obtain the flow field and sound field of 1:25 scale trains with three,six and eight coaches in a long tunnel,and the aerodynamic results were verified by wind tunnel test with the same scale two-coach train model.Time-averaged drag coefficients of the head coach of three trains are similar,but at the tail coach of the multi-group trains it is much larger than that of the three-coach train.The eight-coach train presents the largest increment from the head coach to the tail coach in the standard deviation(STD)of aerodynamic force coefficients:0.0110 for drag coefficient(Cd),0.0198 for lift coefficient(Cl)and 0.0371 for side coef-ficient(Cs).Total sound pressure level at the bottom of multi-group trains presents a significant streamwise increase,which is different from the three-coach train.Tunnel walls affect the acoustic distribution at the bottom,only after the coach number reaches a certain value,and the streamwise increase in the sound pressure fluctuation of multi-group trains is strengthened by coach number.Fourier transform of the turbulent and sound pressures presents that coach number has little influence on the peak frequencies,but increases the sound pressure level values at the tail bogie cavities.Furthermore,different from the turbulent pressure,the first two sound pressure proper orthogonal decomposition(POD)modes in the bogie cavities contain 90%of the total energy,and the spatial distributions indicate that the acoustic distributions in the head and tail bogies are not related to coach number.

关 键 词：Flow and sound fields Scaled high-speed trains Different coach numbers Long tunnel Proper orthogonal decomposition 

分 类 号：U451.3[建筑科学—桥梁与隧道工程]