A fully coupled 3D wave‐current interaction model on unstructured grids

Abstract

We present a new modeling system for wave‐current interaction based on unstructured grids and thus suitable for very large‐scale high‐resolution multiscale studies. The coupling between the 3D current model (SELFE) and the 3rd generation spectral wave model (WWM‐II) is done at the source code level and the two models share same sub‐domains in the parallel MPI implementation in order to ensure parallel efficiency and avoid interpolation. We demonstrate the accuracy, efficiency, stability and robustness of the coupled SELFE‐WWM‐II model with a suite of progressively challenging benchmarks with analytical solution, laboratory data, and field data. The coupled model is shown to be able to capture important physics of the wave‐current interaction under very different scales and environmental conditions with excellent convergence properties even in complicated test cases. The challenges in simulating the 3D wave‐induced effects are highlighted as well, where more research is warranted.