Simulation of shoaling and breaking waves over variable seabed: a comparison of nonlinear deterministic wave models

  • Coulaud, Guillaume (EDF R&D LNHE and Saint-Venant Lab.)
  • Benoit, Michel (EDF R&D LNHE and Saint-Venant Lab.)
  • Teles, Maria (EDf R&D LNHE)

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When ocean water waves propagate from deep water zones towards the shore, they undergo significant changes due to the decrease of water depth, including shoaling, refraction, diffraction, reflexion, bottom friction and depth-induced breaking. Furthermore, dispersive and nonlinear effects play a more or less pronounced role depending on the values of the relative water depth kh (k being the local wave number and h the local water depth) and wave steepness ka (a being the local characteristic wave amplitude). Finding a model which is able to model wave transformation over wide ranges of kh and ka, while properly accounting for depth induced breaking in shallow water remains a challenge. In this study, we compare several deterministic (i.e. phase resolving) waves models for this type of coastal applications, including various long-wave type models of the Boussinesq and Serre-Green-Naghdi (SGN) families (e.g. Nwogu, 1993 [1], Kennedy et al., 2000 [2], Gavrilyuk et al., 2016 [3] among many others), as well as a fully nonlinear potential-flow model, already applied to breaking wave cases (Simon et al., 2019 [4]). These models will be briefly described during the conference, together with the numerical methods used to simulate them numerically. The performances of the models are assessed on several cases in 1DH (x,z) configuration, for which experimental data are available from either regular or irregular wave flume experiments (e.g. Ting & Kirby, 1994 [5]). Special attention is paid to the capabilities and accuracy of the models regarding (i) wave dispersion, (ii) nonlinear effects and (iii) wave breaking dissipation and associated effects (wave set-up, and induced mean circulation in the water column). The simulation of wave run-up on plane slopes will be discussed as well.