A physically based strategy was used to model swash zone hydrodynamics forced by breaking waves within a Boussinesq type of model. The position and the velocity of the shoreline were determined continuously in space by solving the... more
A physically based strategy was used to model swash zone hydrodynamics forced by breaking waves within a Boussinesq type of model. The position and the velocity of the shoreline were determined continuously in space by solving the physically-based equations of the shoreline motion; moreover, a fixed grid method, with a wet–dry interface, was adopted for integrating the Boussinesq model. The numerical stability of the model was improved by means of an extrapolation method. To validate the proposed methodology, the classical analytical solution for the shoreline motion of a monochromatic wave train over a plane beach was considered. The comparison between the analytical and numerical horizontal shoreline movements provided a very good agreement. Several other tests on the run-up of non-breaking and breaking waves were performed as well. These tests showed that the proposed model was always in fairly good agreement with the experimental data, even in complex hydrodynamic situations like those forced by breaking solitary waves. In particular, in comparison with other state-of-the-art shoreline models, in all the analyzed cases the proposed model allowed much better predictions of the shoreline velocity to be obtained.► Physically based Lagrangian shoreline model for highly non-linear Boussinesq models. ► The number of calibration parameters are strongly reduced. ► Evolution of solitary breaking and non-breaking waves considering bottom friction. ► Better and more stable behavior than others method. ► The relative errors in maximum horizontal excursion of the shoreline are less than 1%.
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The dynamics of the wave propagation within the surf zone is represented through a weakly dispersive fully nonlinear Boussinesq-type of model. The flow is assumed rotational and the governing equations are derived with no assumptions on... more
The dynamics of the wave propagation within the surf zone is represented through a weakly dispersive fully nonlinear Boussinesq-type of model. The flow is assumed rotational and the governing equations are derived with no assumptions on the order of magnitude of the nonlinear effects. In the modeling, the velocity field is influenced by the effects of vorticity due to breaking, and the vorticity transport equation is solved analytically. The amount of vorticity introduced by the breaking process is determined through an analogy with the hydraulic jump and the adoption of the concept of the surface roller.A numerical accurate description of the effects of the surface roller is obtained by adopting an original self-adaptive-time-varying grid, developed on purpose. Such an approach makes it possible to get a better resolution in the region with rapid variations where the vorticity is generated, without heavily affecting the efficiency of the numerical model. Comparisons with a weakly nonlinear version of the model show that the proposed model considerably improves the estimate of the dynamics of wave propagations both in the shoaling and in the surf zone.Comparisons with laboratory measurements, both for regular and irregular waves, demonstrate that the proposed model has fairly good prediction capabilities. In particular, in contrast to other models, it provides quite good estimates of both the velocity and the undertow profiles. Moreover, typical features of random wave breaking (such as varying breaking line, different wave height decay, effects of groupiness) can be reproduced by the proposed model, as shown through comparisons with groupy wave laboratory data.