Vortex interaction with free-surface by a coupled FV-SPH solver

Recently, an algorithm for coupling a Finite Volume (FV) method, that discretize the Navier-Stokes equations on block structured Eulerian grids, with the weakly-compressible SPH was presented. The algorithm takes advantage of the SPH method to discretize flow regions close to free-surfaces and of Finite Volume method to resolve the bulk flow and the wall regions. The continuity between the two solution is guaranteed by overlapping zones. Here we extend the algorithm in by adding two new features: 1) creation/deletion of particles at the boundary of the SPH sub-domain; 2) crossing of the free-surface on the coupling region. In this context, particle generation is particularly complex because of the Lagrangian character of SPH, which has to be consistent with the Eulerian description of the flow in the Finite Volume method. We propose here a new technique based on a shifting technique specifically conceived for the coupling procedure. The creation/deletion technique was validated on different test cases with particular attention to mass conservation. On the Finite Volume side, a new technique for free surface capturing, inspired by the Particle Level-Set algorithms, was developed and implemented. The combination the two new features was tested and validated in the case of vortex/free surface interaction. A final application of the new coupled solver is given for a violent sloshing flow in a tank.