A nonoverlapping heterogeneous domain decomposition method for three-dimensional gravity wave impact problems

•A 3D free surface flow model coupling potential flow and viscous flow.•Coupling scheme is based on nonoverlapping heterogeneous domain decomposition methods.•The subproblems are solved using BEM and FEM, respectively.•Nonconforming mesh interpolation and free surface reconstruction at the interface.•The method is validated with experiment data and proved to be accurate and efficient.

A 3D heterogeneous flow model which combines incompressible viscous flow and potential flow both with free-surface boundaries is developed and solved numerically, using finite element method and boundary element method, respectively. The coupled model is solved based on a nonoverlapping domain decomposition method, which reduces the problem to the coupling interface. At the interface, the problem is equivalent to Bernoulli’s equation consisting of mappings from potential/velocity to velocity/pressure. These mappings enable us to design the scheme following the Dirichlet–Neumann method for nonoverlapping domain decomposition, and lead to a staggered scheme. We also discuss data transfer as well as free surface reconstruction at the interface. Errors introduced by the surface reconstruction technique are examined and discussed in detail. The errors from the first-order staggered scheme is also studied. A comparison of numerical prediction with experimental data that the proposed method performs efficiently and accurately for wave impact problems.