Boundary integral equations for sound radiation from a harmonically vibrating body moving uniformly in a free space.

In this high-speed transit era, the prediction of sound radiation from a moving and vibrating object is an important research topic. A typical example is a high-speed train wheel that not only moves fast in the railway direction but, due to wheel/rail interaction, also vibrates at high frequency, generating a complex sound field. By making use of sound spectra generated by moving harmonic compact sources, three-dimensional (3D) boundary integral equations are established in this paper for sound radiation from a harmonically vibrating body moving uniformly in a free space. The 3D boundary integral equations are reduced to 2D ones for a special case in which the body is axisymmetric and moves in its axial direction. The 2D boundary element method is applied to solve the 2D boundary integral equations and to produce results for a pulsating and moving sphere. Results show that the moving speed of the pulsating sphere has a significant effect on the generated sound field. This means that, for sounds radiated from a high-speed train wheel vibro-acoustically, the motion of the wheel has to be taken into account.