Nonlinear wave diffraction due to a vertical structure with arbitrary section and axisymmetric structure

摘要

The general form of the second order solution for the nonlinear wave diffraction is derived in analytical form according to the analytical solution of the second order wave diffraction due to a vertical circular cylinder derived by the present authors. The eigenfunction expansion technique is applied to the structure surface boundary condition of the derived solution to describe the wave fields around a vertical structure with arbitrary cross section and an axisymmetric structure with use of the eigenfunction expansion technique. Laboratory experiments are also conducted to measure the wave deformation due to cylinder with rectangular cross sections and circular cylinders with uneven diameter. The wave height distribution calculated with the present theory is compared to the experimental one. The comparison shows fair agreement between them and the validity of the solution is confirmed. Moreover, the wave height distribution obtained by the second order solution shows quite different wave height distribution, in particular, behind the structure because of the second order free wave components which have shorter wave length.