On the coupling of Incompressible SPH with a Finite Element potential flow solver for nonlinear free surface flows

This paper presents a 2-D one-way coupling methodology between the quasi-arbitrary Lagrange-Euler finite element method (QALE-FEM) (Ma and Yan 2006) which is a nonlinear potential flow solver and incompressible smoothed particle hydrodynamics (ISPH) (Lind et al. 2012), Navier-Stokes equations solver. Nonlinear potential flow solvers such as the QALE-FEM are highly efficient solvers for propagating waves in large domains; however, when extreme nonlinearity takes place such as fragmentation, breaking waves and violent interaction with marine structures, the methodology becomes incapable of dealing with these flow features. A particle method such as ISPH is known to be accurate for such highly nonlinear fragmentized flows with noisefree pressures. ISPH is thus ideal for the near-field and slamming due to its ability to treat highly nonlinear flows and free surface flows with overturning and splashing. Herein, we propose a one-way coupling methodology between QALE-FEM and ISPH where the methods are used for the far field and inner/local regimes respectively. To validate the one-way coupling algorithm a regular wave has been used with satisfactory results. The intention is to extend this approach to strong coupling of the potential flow solver with ISPH using a two-phase (airwater) solver (Lind et al. 2016). The aim is to reliably predict extreme wave forces and slamming on offshore structures such as decks and platforms for marine renewable energy and oil and gas industry.