Coupling of SPH and Volume-of-Fluid for multiphase flow

A new methodology for coupling Smoothed Particle Hydrodynamics (SPH) with a Finite Volume (FV) solver for multiphase flow is presented. The approach follows a patched-domain strategy in which the two domains are disjointly separated by a discrete coupled boundary. Consequently, the coupled SPH–FV method is able to benefit from both methods’ strengths in their respective domains. The SPH solver employs a custom scheme, whereas a preexisting FV solver employing a Volume-of-Fluid (VoF) multiphase representation is adapted with minor modifications. Key features of the coupling include the determination of the volume fraction at the coupled boundary, the preservation of the fluid interface, and surface tension modeling in the vicinity of the coupled boundary. The method is validated against a series of benchmark cases, showing very good agreement. To our knowledge, this is the first coupled SPH–FV method that allows interface advection across the coupled boundary for multiphase flow with surface tension.