A finite element solution of wave forces on a horizontal circular cylinder close to the sea-bed*

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 1.5 D, 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).