Semi-analytical solution of cnoidal wave diffraction around a double-layer arc-shaped vertical porous breakwater

The interaction between the first-order cnoidal wave and a concentric structure with dual-arc porous breakwaters is studied semi-analytically based on eigenfunction expansion. Both arcs of breakwater are considered as thin shell structures rigidly mounted flat sea bottom. fluid domain divided into an unbounded two bounded sub-domains, within which solutions described by eigenfunctions. Matched conditions along boundaries different regions applied, leading to semi-analytical solution problem. method applied study special case diffraction solid cylinder results loads runups agree excellently reference in literature. For double-layer arc-shaped vertical standing shallow-water waves where theory applicable, our show that approach using linear Airy may significantly underestimate breakwater. It also shown has better protective performance than single-arc Parametric studies porosity, annular spacing, opening angle, water depth incident angle presented.