Three-dimensional wave scattering by a fixed cylindrical inclusion submerged in a fluid medium

Abstract

This paper presents the solution for a fixed cylindrical irregular cavity of infinite length submerged in a homogeneous fluid medium, and subjected to dilatational point sources placed at some point in the fluid. The solution is first computed for a wide range of frequencies and wavenumbers, which are then used to obtain time-series by means of (fast) inverse Fourier transforms into space–time. The method and the expressions presented are implemented and validated by applying them to a fixed cylindrical circular cavity submerged in an infinite homogeneous fluid medium subjected to a point pressure source for which the solution is calculated in closed form. The boundary elements method is then used to evaluate the wave-field elicited by a point pressure source in the presence of fixed rigid cylindrical cavities, with different cross-sections, submerged in an unbounded fluid medium and in a half-space. Simulation analyses with this idealized model are then used to study the patterns of wave propagation in the vicinity of these inclusions. The amplitude of the wavefield in the frequency vs axial-wavenumber domain is presented, allowing the recognition, identification, and physical interpretation of the variation of the wavefield.