On the interaction of a solitary wave and a submerged dike

The unsteady, two-dimensional Navier-Stokes equations and the exact free su rface boundary conditions were solved to study the interaction of a solitar y wave and a submerged dike. A piston-type wavemaker was set up in the comp utational domain to produce the incident solitary waves. The incident wave and the associated boundary layer flow in a wave tank with a flat bed were compared with the analytical solutions to verify the accuracy of this numer ical scheme. Effects of the incident wave height and the size of the dike o n the wave transformation, the flow fields, and the drag forces on the dike were discussed. Our numerical results showed that even though the induced local shear stress on the top surface of the dike is large at some particul ar locations, the resultant pressure drag is much larger than the friction drag. The primary vortex generated at the lee side of the dike and the seco ndary vortex at the right toe of the dike may scour the bottom and cause a severe problem for the dike. (C) 2001 Elsevier Science B.V. All rights rese rved.