Scattered sound power from a rigid structure using non-negative intensity

In this work, the non-negative intensity is used to predict the scattered sound power from a rigid structure excited by incident plane waves. The scattered sound power is also predicted from the scattered acoustic intensity integrated over the surface area of the rigid structure, whereby the scattered acoustic intensity is obtained from the scattered sound pressure and scattered particle velocity at the structural surface. The scattered sound power from a rigid sphere under plane wave excitation using the two numerical intensity-based techniques is compared. Furthermore, the scattered acoustic intensity in the far field is evaluated from the scattered sound pressure and scattered velocity at three different shapes for a far-field boundary enclosing the rigid sphere, corresponding to a sphere, a half sphere and a cube. The scattered sound power based on integration of the far-field scattered acoustic intensity and calculated from the surface of the scatterer are then compared.