A Combined Level Set/Ghost Cell Immersed Boundary Representation for Simulations of Floating Bodies

Abstract

A six degrees of freedom (6DOF) algorithm is implemented in the open-source CFD code REEF3D. The model solves the incompressible Navier–Stokes equations. Complex free surface dynamics are modeled with the level set method based on a two-phase flow approach. The convection terms of the velocities and the level set method are treated with a high-order weighted essentially non-oscillatory discretization scheme. Together with the level set method for the free surface capturing, this algorithm can model the movement of rigid floating bodies and their interaction with the fluid. The 6DOF algorithm is implemented on a fixed grid. The solid-fluid interface is represented with a combination of the level set method and ghost cell immersed boundary method. As a result, re-meshing or overset grids are not necessary. The capability, accuracy, and numerical stability of the new algorithm is shown through benchmark applications for the fluid-body interaction problem.