Diffraction of Nonlinear Waves by Founded Horizontal Rectangular Cylinder

Abstract

A solution to the diffraction problem for second-order surface waves by a horizontal rectangular cylinder founded on a rubble base is presented. The solution was obtained by the method of matched eigenfunction expansions. Wave load on a cylinder was found by analytical integration of pressure over the wetted surface of a cylinder. The results show that the cylinder width has a significant effect on second-order vertical force and surprisingly little effect on second-order horizontal force, while the cylinder draft has a significant effect on second-order horizontal force and surprisingly little effect on second-order vertical force. Moreover, the results show surprisingly little effect of rubble base damping properties on second-order wave load. The solution reveals significant second-order load on a founded cylinder. The second-order load components may exceed by many times the corresponding first-order quantities. This phenomenon occurs within the commonly accepted range of the applicability of a second-order wave theory.