Radiation and diffraction of sound from bodies mounted on an infinite baffle using Boundary Element Method

This paper presents a Boundary Element formulation for solving the radiation and diffraction of sound from bodies mounted on an infinite baffle. The method is based on the Helmholtz integral equation wherein the sound pressure in the field can be expressed as an integral of the pressure and particle velocity over the surface of the body. By using an appropriate Green's function the integration over the infinite plane is avoided. Numerical implementation is done by discretizing the surface into elements and integrations are evaluated using simple Gaussian formula. A special coefficient for the pressure in the field is derived due to the contact phenomenon between the body and the infinite plane. It turns out that the information of the acoustic variables on the contact plane are not required. The elements on the contact plane are thus dummy elements that are needed only for the calculation of the coefficient of the pressure in the acoustic field. The formulation are applicable for any arbitrary shape body mounted on an infinite baffle.