Study on the aerodynamic noise characteristics of high-speed pantographs with different strip spacings

Abstract In order to study the effect of the strip spacing on the aerodynamic noise characteristics of the pantograph of high-speed train, the numerical simulation of the aerodynamic flow behavior for the high-speed pantograph is conducted using the detached eddy simulation (DES) and its aerodynamic noise is studied using the FW-H model. The numerical method is verified by flows around a cylinder with a finite span. The numerical results show that the strip spacing has a great effect on the aerodynamic characteristics of the pantograph. When there is only one strip, the aerodynamic drag force is reduced by 10.4% compared with the double-strip pantographs. The fluctuation in pressure on the strip and the fluctuation in lift force of the panhead are the smallest. The aerodynamic drag force of the double-strip pantograh increase with the incremental of the strip spacings. Under different strips spacings, the vortex structure around the panhead is different, and the inappropriate strip spacing will aggravate the fluctuation in forces due to the vortex shedding from the strip. The vortex shedding frequencis are mainly 270Hz, 540Hz, 820Hz. Meanwhile, the strip spacing has few effect on the frequency of vortex shedding. The radiated noise from the pantograph is transmitted in the form of a spherical wave. When the strip spacing is 0 ​mm or 540 ​mm, the sound pressure level of the far field radiation noise of the pantograph is smaller. The energy of the far field aerodynamic noise of the pantograph is mainly concentrated in the frequency range of 200–1600 ​Hz. For a pantograph with double-strip, when the spacing is 540 ​mm, the sound pressure level at the noise measurement point (25m, 0, 3.5m) is the smallest. Whereas the strip spacing is 475 ​mm, the sound pressure level is the largest and the difference reaches 2.8 dBA.