国产欧美精品一区二区,中文字幕专区在线亚洲,国产精品美女网站在线观看,艾秋果冻传媒2021精品,在线免费一区二区,久久久久久青草大香综合精品,日韩美aaa特级毛片,欧美成人精品午夜免费影视

With the increasing of high-speed train speed, the aerodynamic noise problem increasingly prominent. The pantograph noise represents a higher position in the train noise, in order to study the aerodynamic noise characteristics of the pantograph of high-speed train, The Broadband noise model based on Lighthill acoustics theory is used to identify the aerodynamic noise sources of high-speed trains, the SST k-w turbulence model is used to analyze the flow field characteristics of the pantograph；Based on the large eddy simulation and the FW-H acoustic theory , the aerodynamic noise characteristics of the pantograph is caculated. The numerical examples show that, The carbon skateboard and bow head of the pantograph are the main noise sources of the pantograph; With the center line of train, the sound pressure level and spectrum characteristics of the far field aerodynamic noise monitoring points show high symmetry; At the same train speed, the sound pressure level at the monitoring point decreases with the distance from the Central Line of the track increasing, when the train runs at different speeds, the amplitude of the sound pressure level decrease is small; The aerodynamic noise in the far field of high-speed train is broadband noise, and the main energy concentration is 500Hz~5000Hz. A method of jet noise reduction was proposed. At the velocity of 350km/h, the total sound pressure level of the monitoring point decreased by 15.2dB.