Predicting the wind noise from the pantograph cover of a train
Finite element and boundary element calculations are combined to predict the how noise radiated from a 1/10th-scale model of an aerodynamic cover used around the pantograph on a train at 250 km h(-1). The solutions of the unsteady air how over the cover and the resulting sound propagation are divided into two parts in order to keep the problem tractable. First the unsteady fluid flow is solved using large-eddy simulation (LES). The pressure histories on the cover are then used to predict the radiated sound, using a boundary element method to solve the Helmholtz equation. The result thus leans heavily on assumptions about the coupling of the two solutions, the propagation of sound in a disturbed medium and the efficacy of LES. The predicted sound pressure levels are compared with experimental measurements made in an anechoic wind tunnel. (C) 1997 by John Wiley & Sons, Ltd.
wind noise large-eddy simulation helmholtz equation aeroacoustics time-dependent incompressible flows acoustic boundary elements