Severe Wave-Body Interactions: a Potential-Flow HPC Method and its Strong Domain-Decomposition Coupling with a Level-Set Navier-Stokes Solver

The main objective of our ongoing research is to investigate wave loads on and motions of floating bodies in steep waves. For modelling non-linear water-wave and wave-body interaction problems, researchers can use two main classes of numerical methods, where the preferred choice depends on the features of the problem. One class consists of potential-flow solvers, which are efficient and accurate in simulating propagating waves. In this framework, we have proposed a method based on the high-order harmonic polynomial cell (HPC) method at the 32nd IWWWFB. In [1], its ability to simulate a variety of wave-propagation problems has been demonstrated in detail, even for steep waves close to breaking. The other class consists of more computationally expensive NavierStokes solvers, able to deal with problems involving wave breaking and fragmentation phenomena and/or important viscous effects. To benefit from the strengths of both classes of solvers, couplings between potentialflow and Navier-Stokes solvers have received increased attention in the research community during the last years. In this framework, in [2], we proposed a 2D strong Domain-Decomposition (DD) strategy between a Level-Set Navier-Stokes (LS-NS) solver and a non-linear potential-flow solver based on the boundary element method (BEM) to analyze a dam-breaking problem and subsequent wave impact on a vertical wall. Here, the HPC-based potential-flow (HPC-PF) solver's capability to handle wave-body interactions, when viscous effects are limited, is documented by comparing against the BEM and available experiments. Then, a 2D strong DD strategy between the HPC-PF solver and the LS-NS solver is proposed to handle more general scenarios and enhancing accuracy and efficiency with respect to using the BEM solver.