SEDIMENT TRANSPORT BY WAVE PLUNGING INDUCED VORTICES INVESTIGATED FROM DEM-MPS SIMULATION

Abstract

 A detailed understanding of the sediment transport mechanisms induced by breaking waves can enhance the accuracy of the sediment flux modeling. Process-based numerical simulations can reveal the hydrodynamics of breaking waves, and the authors have investigated the sediment transport under breaking waves from the grain scale using Lagrangian models, which have advantages in application for breaking waves. However, the discussions were limited to a narrow channel, and further discussions were required.

 This study used a DEM-MPS scheme to conduct a three-dimensional sediment transport simulation in an oscillating water tank. After comparatively validating the simulation results from PIV measurements we performed in a corresponding condition, the vortex structures under plunging waves are visualized. Extracted velocity fields with certain spatial scale bands illustrated that vortex filaments with rotating axes perpendicular to the wave crest were aligned and that their scale was a quarter of horizontal roller. We also describe the contribution of the vortex filaments with the pressure fluctuation to the local sediment transport.