This paper describes impulsive wave force due to breaking solitary waves impinging and overtopping an impermeable breakwater upon a sloping beach. A two-dimensional volume of fluid (VOF) type numerical model named COBRAS (COrnell BReaking And Structure), based on the Reynolds-Averaged Navier-Stokes (RANS) equations and the k - ε turbulence closure model, is firstly calibrated against present laboratory experiments with fairly good agreements and then employed to study the impulsive wave force correlated with structure failure mechanisms due to waves interacting against the breakwater. Both the effects of wave nonlinearity and freeboard are addressed. Influence of entrapped air-bubble accompanied breaking waves on reducing wave force is also discussed.
Historical tsunami survey literature points out that the devastating tsunami power is relevant to wave run-up inundation combined with floating debris on shorelines, in which significant wave force of impulsive tsunami wave could destroy inland community and alongshore infrastructure (e.g. Yamamoto et al., 2006). Various impulsive waves would occasionally give rise to different structure failure mechanisms (Kato et al., 2005), and also allow particular wave dynamics to affect alongshore flow fields on structure damage (Tokin et al., 2003). The knowledge of wave-structure interaction is therefore of crucial importance for tsunami hazard mitigation. Over the past decades it can be seen that the subject of wave-structure interaction under solitary-like long waves have been received marvelous attention on tsunami wave research (Synolakis and Bernard, 2006), such as run-up/run-down on a sloping beach (e.g. Lin et al., 1999; Hsiao et al., 2008), disintegration and transmission properties of waves over an abrupt topography (e.g. Losada et al., 1989; Liu and Cheng, 2001), and dynamic vortex shedding and advection around a submerged obstacle or a sub-aerial plate (e.g. Chang et al., 2001). However, the information combined solitary wave impingement with overtopping flow upon a coastal structure is relatively rare.
