Numerical Study on Aerodynamic Noise Reduction of Pantograph

Abstract

A hybrid method incorporating the simulations of noise sources with delayed detached eddy simulation (DDES) and calculations of far-field noise with the Ffowcs Williams–Hawkings (FW-H) equation is used to study the suppression technique for the aerodynamic noise of a Faiveley CX-PG pantograph. Considering that China’s Fuxing bullet trains operate at 350 km/h, the inflow velocity of 350 km/h is applied in this paper. The noise radiated from the panhead area, middle area, and bottom area at an inflow velocity of 350 km/h is distinguished. The noise intensities at the standard observer show that the noise radiated from the panhead area is the strongest, and the sound pressure level spectrum value is larger than the other two in the range above 500 Hz. The influence of applying the wavy rods and modifying the contact strip shape on the aerodynamic noise is discussed in detail. By comparing the acoustic source distribution and the far-field noise intensity, it is found that applying the wavy rods can effectively reduce the panhead noise, especially around the peak frequency. Modifying the shape of the contact strip to a hexagon can suppress the vortex shedding, leading to a lower surface pressure level. Combining the strip modification and wavy rods, the total noise intensity can be diminished by about 3.0 dB.

Special Issue on Aerodynamic Noise Research of High-Speed Trains

“…The airfoil bow head reduces the vorticity intensity and vortex structure scale size, thus reducing the intensity of the radiated noise by about 1.2 dBA. In addition, the application of waviness to the surface of the pantograph rod or the usage of a contact strip with a hexagonal cross-section can reduce the pressure level on the surface of the pantograph, thus achieving noise reduction [6]. The implementation of wavy rods effectively reduces the panhead noise, while modifying the shape of the contact strip into a hexagon helps suppress vortex shedding.…”