A FINITE ELEMENT SOLUTION OF WAVE FORCES ON A HORIZONTAL CIRCULAR CYLINDER CLOSE TO THE SEA-BED

摘要

A numerical model is established for simulating the wave action on a horizontal circular cylinder close to the sea-bed. The two-dimensional Navier-Stokes (NS) equations are solved by a finite element method. The arbitrary Lagrangian-Eulerian scheme is employed for tracking the moving free surface boundary. After each computational time step, the mesh is updated by solving a linear equilibrium equation of elasticity. In front of the outgoing boundary a damping layer is set to absorb the wave energy. The computation is carried out for the gap between the cylinder and sea bed (e) ranging from 0.1 to 1.5D, with D being the cylinder diameter, and the Reynolds number about 1800. The computed wave force coefficients and velocity fields are verified by the experimental results reported by Jarno-Druaux et al. (1995).