Numerical modeling of wave breaking induced by fixed or moving boundaries

Journal of Fluid Mechanics 294, 71-92, 1995.

Ge Wei           and         James T. Kirby          and        Stephan T. Grilli       and      R. Subramanya

Graduate student          Professor                                  Associate Professor           Graduate student
UoD                               Department of Civil Eng.        University of Rhode Island                          
                                       Newark, DE 19716, USA        Narragansett, RI 02882, USA                    

Abstract :  

Fully nonlinear extensions of Boussinesq equations are derived to simulate surface wave propagation in coastal regions. By using the velocity at a certain depth as a dependent variable (Nwogu, 1993), the resulting equations have significantly improved linear dispersion properties in intermediate water depths when compared to standard Boussinesq approximations. Since no assumption of small nonlinearity is made, the equations can be applied to simulate strong wave interactions prior to wave breaking. A high order numerical model based on the equations is developed and applied to the study of two canonical problems: solitary wave shoaling on slopes and undular bore propagation over a horizontal bed. Results of the Boussinesq model with and without strong nonlinearity are compared in detail to those of a boundary element solution of the fully nonlinear potential flow problem developed by Grilli et al. (1989). The fully nonlinear variant of the Boussinesq model is found to predict wave heights and particle kinematics more accurately than the standard approximation, while phase speed predictions are not uniformly improved.

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