The noise from Maglev consists mostly of an aeroacoustic sound. Measurement with a sound concentrating microphone with a paraboloidal reflector at the Yamanashi test line verifies that there is an intensive sound source around the front fairings of the front bogie. Flow visualization with a 1/6.25 scale model at the Maibara wind tunnel shows that a flow has an upward component at the bogie section because the space between the body and the side wall becomes narrow. The aeroacoustic noise is not generated by the front shape itself, but by the gaps between the fairings around the bogie. The flow with an upward component separates at the irregular fairings deformed aerodynamically, and sheds vortices. A new front shape which moderates the flow around the front fairings proves to reduce the aeroacoustic noise.

Copyright (c) 2001 Railway Technical Research Institute