On the Use of a BEM Time-Stepping Procedure for Nonlinear and Unsteady Wave-Structure Interaction

Abstract

Computer aided analysis of fluid-structure interaction in ocean engineering problems requires efficient and reliable numerical methods. Due to free surface flow and gravity waves they have to consider: large and arbitrary shaped domains, free and moving surfaces, i e nonlinear and time-dependent boundary conditions. Assuming a two-dimensional potential flow, the direct boundary element formulation (BEM) is the most efficient solution method. Compared to other discretization methods it has minimum discretization expenses, a better representation of complex boundary geometries, and a simple approach to moving boundaries. This is achieved by coupling the BEM with a timestepping procedure. For numerical simulation of time-dependent, nonlinear (overturning) gravity waves this approach, introduced by Longuet-Higgins and Cokelet [10], now is an optimized and reliable method in use, [6, 7,12, 14]. Recently even a three-dimensional wave analysis is proposed: [1, 3, 15, 20]. The extension of this BEM time-stepping approach to wave-structure interaction is reasonable, [19], especially to wave channel simulations, [6, 18]. A direct BEM formulation allows for different kind of boundary conditions on each finite boundary element. Hence, this proposal pay regard to a wide range of different wave-structure interaction problems, ref. Fig. 1.1.