Analysis on the aerodynamic noise of the pantograph of high-speed train at 400 km/h

In order to clarify the aerodynamic noise characteristics of the high-speed train pantograph system and its relationship with the flow field, a subdomain model of the full size and a scale model of the pantograph were established, and large eddy simulation, acoustic perturbation equation and FW–H equation were used to predict the flow field and sound field under the condition of rising bow at 400 km/h. Based on the FW–H equation, the sound source distribution was inverted, and the energy distribution of the turbulent pressure and sound pressure in the pantograph base were analyzed using the reduced order model. The results show that with the incoming flow velocity of 400 km/h and the pantograph as the sound source, the total sound pressure level of P2, which is the standard measuring point in the far field can reach 88.1 dB(A), and there are obvious peaks around 283 Hz and 576 Hz. The Strouhal number corresponding to the peak frequency (characteristic length is 41 mm equivalent diameter of the square rod) is 0.10 and 0.21, respectively. The energy ratio of the first two modes of the turbulent pressure and sound pressure in the pantograph base are 4.5% and 3.3%, 40.9% and 14.0%, respectively, with certain symmetry in the distribution. For the pantograph base, in the frequency band below 300 Hz, the pressure level of the full-size model is larger than that of the scale model, and in the frequency band below 1000 Hz, the sound pressure level of the full-size model is larger than that of the scale model. When the whole pantograph is used as the sound source to radiate to the far-field standard point, the measured sound pressure level of the full-size model is larger than that of the scale model at all frequencies.