Application of Free-Surface Immersed-Boundary Lattice Boltzmann Method to Waves Acting on Coastal Structures

Abstract

A free-surface immersed-boundary lattice Boltzmann method for wave–structure interaction and hydrodynamic force estimation is introduced as a proposed model with example applications. The single-phase free-surface lattice Boltzmann method is coupled with a simple immersed-boundary modification in order to simulate demanding free surface wave problems and to evaluate the hydrodynamic forces on a breakwater. The immersed-boundary modification also enables a seepage flow simulation without any external model. First, the proposed model is applied to incident wave propagation in a shallow water zone to demonstrate the model performance on traveling successive waves and wave effects on groundwater on a porous slope. The wave–breakwater interactions and wave forces on a breakwater are then analyzed. The results agree with those of Goda’s formulae in all cases and with the third-order force expression from standing wave theory in nonoverflowing cases, confirming that the proposed model has a high potential for application to complex analysis of coastal engineering problems.