Implementation of the Ghost Fluid Method for free surface flows in polyhedral Finite Volume framework

This paper presents an extension of the Ghost Fluid Method to arbitrary polyhedral Finite Volume framework for free surface flow simulations, primarily intended for marine hydrodynamics applications. Two immiscible, incompressible fluids are implicitly coupled via interface jump conditions, allowing the formulation of a single set of equations for both fluids. The jump conditions at the free surface are discretised with one sided extrapolates, using a compact computational stencil in second-order accurate, collocated polyhedral Finite Volume Method. The free surface is captured using the Volume-of-Fluid method with an additional compressive term. Even though the Volume-of-Fluid method is used, density and dynamic pressure exhibit sharp distribution at the interface due to jump conditions. The paper also demonstrates how the conditionally averaged equations with segregated solution algorithms cause spurious velocities at the free surface, which are resolved by the present approach since the Ghost Fluid Method relocates the pressure-density coupling inside the pressure equation. The method is implemented in OpenFOAM Computational Continuum Mechanics software, and the verification and validation is performed on two sets of test cases: free surface flow over a ramp and a steady resistance simulation of a container ship free to sink and trim.