In this paper, we develop a mass-force coupling model for simulation of the motion of a moving body in waves, based on our highly efficient Navier-Stokes solver (Li et al., 2004; 2006), named LVOF. LVOF is constructed by a novelVOF finite volume cut-cell approach, coupled with a dynamic subgrid-scale (SGS) model. By explicitly tracking the interface as a set of curves in 2D or a planar interface in 3D (where the location of the object in the grid is described with coefficients of the volume and area fractions), we capture the solid-liquid phase front over a fixed Cartesian grid without smearing the information at the particle-fluid interface. The rigid body distributed over the particle domain is treated as a fluid. Furthermore, the dynamic coupling between the particle and fluid phases is realized by adding mass and force terms into the continuity and momentum equations as a net driving force, acting on varying fluid elements. Grid refinement studies are performed for test problems involving the wedge entry and motion of a body prescribed in waves. Additionally, issue about the convergence performance is addressed. Under the prescribed entry velocity, we also concern water entry of a circular cylinder. Very encouragingly, the results agree well with measurements available. It is demonstrated that most of typical features in complex flow patterns can be captured in waves superimposed on the following currents, by using LVOF.
Being one of the challenging topics in CFD, fluid-body coupling is the particular problems of interest. It arises in many different areas of engineering. More importantly, the presence of surface water waves substantially aggravates the situation that may change the environments. In ship and offshore structures, for example, an extreme case is that a ship travelling in heavy sea can be characterized by bow-flare water impact in waves.