SPH energy balance during the generation and propagation of gravity waves

This work presents an energy analysis of the time behaviours of mechanical and internal fluid energies during generation and propagation of gravity waves. The analyses are performed through the delta -SPH model, which is a Smoothed Particles Hydrodynamic (SPH) variant based on a weakly-compressible fluid approximation. The solid boundary techniques adopted are: the ghost and the fixed ghost particles. A first problem in which the dynamic is generated by a water patch falling into a still water tank is analyzed. In this case, the dissipation processes due to the diffusive and viscous numerical corrections are investigated. Then, a problem of relevant interest in coastal engineering field, concerning the wave generation and propagation in a wave flume, is studied. Particular attention is given to the analysis of the energy introduced in the fluid domain as the work made by the moving solid boundary on the fluid mass. Then, a comparison of the time evolution of the energy components is presented for a wave reflecting case, characterized by a flat bottom flume with a vertical wall, and a wave absorbing case, characterized by a flume with a sloping bottom end.