Abstract:

An alternative formulation is derived for predicting acoustic radiation from a vibrating object in an unbounded fluid medium. The radiated acoustic pressure is shown to be expressible as a surface integral of the particle velocity, which is determinable by using a nonintrusive laser velocimeter. This approach is in contrast with the Kirchhoff integral formulation which requires the knowledge of both the normal component of the surface velocity and the surface acoustic pressure prior to predicting of the radiated acoustic pressure. Solutions thus obtained are unique. Moreover, the efficiency of the numerical computations is high because the surface integration can be readily implemented numerically by using standard Gaussian quadratures. Such a formulation can be readily extended to acoustic scattering problems and acoustic radiation in an interior region. This alternative formulation may be desirable to analyze the acoustic and vibration responses of a lightweight, a flexible, or a structure under an adverse environment for which a nonintrusive laser measurement technique must be used. Validations of this alternative formulation are demonstrated both analytically and numerically for vibrating spheres and right circular cylinders. [Work supported by NSF.]