Non-hydrostatic modeling of wave interactions with porous structures

This paper presents a three-dimensional non-hydrostatic wave model NHWAVE for simulating wave interactions with porous structures. The model calculates the porous media flow based on well-balanced volume-averaged Reynolds-averaged Navier-Stokes equations (VARANS) in σ coordinate. The turbulence field within the porous structures is simulated by an improved k-ε model. To account for the temporally varying porosity at the grid cell center introduced by the variation of free surface elevation, the porosity is updated at each time step in the computation. The model is calibrated and validated using a wide range of laboratory measurements, involving dam-break flow through porous media, 3D solitary wave interactions with a porous structure, 2D solitary wave interactions with a submerged permeable obstacle as well as periodic wave breaking over a submerged porous breakwater with steep slopes. The model is shown to be capable of well simulating wave reflection, diffraction, wave breaking and wave transmission through porous structures, as well as the turbulent flow field around the permeable structures. It is also demonstrated in the paper that the current non-hydrostatic model is computationally much more efficient than the existing porous flow models based on VOF approach. The non-hydrostatic wave model NHWAVE can be a useful tool for studying wave-structure interactions.