Prediction of sound scattering and radiation using non-negative intensity

Non-negative intensity is a numerical technique based on acoustic radiation modes and using either the acoustic pressure or normal velocity on the surface of the structure, to identify the surface areas of a structure that contribute to sound power. In contrast to acoustic intensity, nonnegative intensity is always positive. In this work, both scattered and radiated sound of structures submerged in a heavy fluid medium are considered. For the scattering problem, several rigid structures corresponding to a sphere, a cylinder and a hemispherical shell under incident plane wave excitation are examined. For the radiation problem, several elastic structures corresponding to a spherical shell, a cylindrical shell and a hemispherical shell under point force excitation are considered. The scattered and radiated acoustic intensities and non-negative intensities of the aforementioned structures are calculated and compared.