SPH Simulation of Onshore Bores with Counter Rotational Vortical Structure

The generation and evolution of two-dimensional bores are analyzed numerically by using the Smoothed Particle Hydrodynamics (SPH) method. With this tool the bore steepening, breaking and post-breaking phases have been detailed investigated in the cases of constant and variable water depths. The bores were generated through a piston wavemaker moving with constant speed and the flow features have been studied by varying the water-depth Froude number from 0.5 to 0.95. The breaking of a plunging bore on the underlying water injects a cyclic process of splashes up with different strengths. The analysis highlighted also the occurrence of clockwise and anti-clockwise vortices, later pairing to form dipole structures. These affect the water evolution and can interact in a complex way with the free surface and with the sea floor. In the latter case, large stresses can be induced at the bottom that are responsible for instance for erosion.