Hydrodynamic response of oblique wave interaction with a pair of submerged H-type breakwaters

This paper models the interaction of obliquely incident waves with a pair of submerged H-type breakwater structures in a fluid of uniform depth, to analyze the resulting hydrodynamic responses. The breakwaters, characterized by rigid vertical and horizontal plates forming an “H” shape in cross section, are symmetrically placed about the central vertical axis of the domain. This geometric symmetry enables the decomposition of the velocity potential into symmetric and antisymmetric components, simplifying the mathematical treatment without compromising physical accuracy. The primary objective is to investigate the hydrodynamic behavior of the system, including wave scattering, reflection, transmission, and the associated wave-induced forces and overturning moment on the structure. The governing boundary value problem involves solving the modified Helmholtz equation under linearized free surface conditions, rigid boundary constraints on the breakwater surfaces and seabed, edge singularity conditions, and appropriate conditions at infinity. The problem is reduced to a system of singular integral equations, which is then solved approximately using a Singularity-Respecting Galerkin Approximation to accurately capture the square-root behavior of the velocity potential near sharp structural edges. Extensive numerical simulations are carried out to investigate the wave–structure interaction characteristics and assess the influence of varying wave conditions on the overall hydrodynamic behavior of the breakwater system. An important result obtained from the configuration analysis suggests that the submerged H-type structure can be a favorable option for practical deployment when the horizontal and vertical plates are of equal length.