Interaction of cnoidal waves with an array of vertical concentric porous cylinders

•We obtain semi-analytical solutions for hydrodynamic loads and wave run-up.•The variation of wave force and wave run-up with different parameters is investigated.•The nature of diffraction effect vary with scattering parameter ka.•Cylinders that are not directly exposed to incident cnoidal waves are more easily influenced by diffraction effect.•The pattern of wave run-up with different parameters vary with the location of cylinders.

An array of large concentric porous cylinder arrays is mounted in shallow water exposed to cnoidal waves. The interactions between waves and cylinders are studied theoretically using an eigenfunction expansion approach. Semi-analytical solutions of hydrodynamic loads and wave run-up on each cylinder are obtained using first approximation to cnoidal waves. The square array configuration of four-legged identical concentric porous cylinder is investigated in present study. Numerical results reveal the variation of dimensionless wave force and wave run-up on individual cylinder with angle of incidence, porosity parameter, spacing between outer and inner cylinders, spacing between concentric porous cylinders and wave parameter. Different mechanism of wave force is found under different range of scattering parameter.