Near trapping phenomena in arrays of porous vertical cylinders

Abstract

The near trapping phenomena are associated with the wave trapping in arrays of large number of solid bodies, which experience increased amplitudes of free-surface elevation between adjacent bodies, and corresponding large wave loads on each array element. In relevant situations of infinite arrays, the wave energy is trapped within the array allowing only a small amount of energy to radiate to the far field, forming the so-called trapped mode phenomenon. The question which this paper tries to answer is whether trapped waves are simulated by arrays of porous vertical cylinders. To tackle this task, a solution method that solves the corresponding diffraction problem by the application of the multiple scattering approach, for the simulation of the hydrodynamic interactions between the waves and the elements of the array, is proposed. Numerical results for several geometrical configurations are presented and discussed, highlighting the effect of porous cylinders on the exerted hydrodynamic loads on the array.