This study introduces a novel flow-through cowcatcher with integrated inlet and outlet channels as an aerodynamic noise mitigation strategy for the nose car of a high-speed train.The wall-adapting local eddy-viscosity...This study introduces a novel flow-through cowcatcher with integrated inlet and outlet channels as an aerodynamic noise mitigation strategy for the nose car of a high-speed train.The wall-adapting local eddy-viscosity large eddy simulation(WALE-LES)combined with the Ffowcs Williams-Hawkings(FW-H)acoustic analogy approach is employed to evaluate its impact on the aerodynamic and aeroacoustic characteristics of the leading bogie region.Compared with the conventional closed cowcatcher,results show that the flow-through structure suppresses the flow separation,promotes more stable vortex evolution within the bogie cavity,and reduces the spatial extent of high amplitude wall pressure fluctuations up to 40%,mitigating effectively the generation of aerodynamic noise.Semi anechoic wind tunnel experiments validate the simulation results and demonstrate that the sound pressure levels at the far field observers decrease by 0.4-0.6 dB(A)with the flow-through cowcatcher applied underneath the nose car.The dominant sound source around the leading bogie region is shrunk with intensity reduced about 1.0 dB(A).These findings confirm the effectiveness of the flow-through cowcatcher in reducing the aerodynamic noise produced from the leading bogie region,providing both theoretical insight and engineering guidance for structural optimization and low-noise design of the nose car in a high-speed train.展开更多
基金Projects(51875411,52232013)supported by the National Natural Science Foundation of ChinaProject(19DZ2290400)supported by the Shanghai Professional Technical Service Platform Program,China。
文摘This study introduces a novel flow-through cowcatcher with integrated inlet and outlet channels as an aerodynamic noise mitigation strategy for the nose car of a high-speed train.The wall-adapting local eddy-viscosity large eddy simulation(WALE-LES)combined with the Ffowcs Williams-Hawkings(FW-H)acoustic analogy approach is employed to evaluate its impact on the aerodynamic and aeroacoustic characteristics of the leading bogie region.Compared with the conventional closed cowcatcher,results show that the flow-through structure suppresses the flow separation,promotes more stable vortex evolution within the bogie cavity,and reduces the spatial extent of high amplitude wall pressure fluctuations up to 40%,mitigating effectively the generation of aerodynamic noise.Semi anechoic wind tunnel experiments validate the simulation results and demonstrate that the sound pressure levels at the far field observers decrease by 0.4-0.6 dB(A)with the flow-through cowcatcher applied underneath the nose car.The dominant sound source around the leading bogie region is shrunk with intensity reduced about 1.0 dB(A).These findings confirm the effectiveness of the flow-through cowcatcher in reducing the aerodynamic noise produced from the leading bogie region,providing both theoretical insight and engineering guidance for structural optimization and low-noise design of the nose car in a high-speed train.
