On a novel application of the Helmholtz integral in the development of a virtual sonar

A novel application of the Helmholtz integral is presented in the development of a virtual sonar. Given total pressure and normal velocity information over the surface of a structure which has been excited both by incident fields as well as interior noise sources, when the Helmholtz integral is evaluated at field points located within the surface of the structure (using the free-space Green's function characteristic of the exterior medium), only the incident field remains. Therefore, it is possible to remove the effects of both scattering (due to incident excitation) and radiation (due to interior noise sources) throughout a ''virtual'' volumetric sonar array projected within the structure. This approach will be discussed and demonstrated using numerical results based on finite element simulations. (C) 2000 Acoustical Society of America. [S0001-4966(00)00112-0].