Analytical modeling of water wave diffraction by arrays of non-concentric porous dual cylinders

An analytical model based on linear potential flow theory is developed to investigate wave diffraction by an array of vertical cylinders enclosed within non-concentric porous walls, employing eigenfunction expansions and Graf’s addition theorem. The analytical formulation is systematically validated against published analytical solutions, numerical results, and wave-flume experimental measurements, demonstrating excellent accuracy and reliability. The eccentricity of the porous enclosure breaks the symmetry of the annular fluid domain and induces a pronounced redistribution of hydrodynamic loads among the cylinders. As the radius ratio increases, the wavenumbers corresponding to minimum hydrodynamic forces progressively shift toward lower values, accompanied by an overall increase in the baseline load level. Wall permeability exerts a dual and contrasting influence on the hydrodynamic response: increasing porosity enhances energy dissipation through the porous wall, thereby suppressing wave run-up on the outer wall, but simultaneously promotes wave transmission and intensifies wave excitation and run-up around the inner cylinders. The proposed analytical solution exhibits rapid convergence and maintains high computational accuracy with a relatively low truncation order, providing an efficient framework for elucidating the coupled effects of structural eccentricity, radius ratio, and wall permeability on wave–structure interactions.