Navier-Stokes solver for water entry bodies with moving Chimera grid method in 6DOF motions

A preconditioned Navier-Stokes (NS) method is developed for multiphase flow with application to the water entry problem of moving bodies. The method employs a dual time-preconditioned technique with multiblock and parallel computing to improve the computational productivity. Novel, generalized pseudo-time terms are added into the multiphase NS equations, taking advantage of two previous suggestions reported in the literature. The NS solver is formulated in the moving curvilinear coordinate system for multiphase flow, including water, vapor, and air fluids. In order to handle the motion of an object in three-dimensional (3D) water entry problems, a six degrees-of-freedom (6DOF) rigid body motion model and a moving Chimera grid scheme are dynamically integrated into the NS solver. The Chimera domain decomposition scheme uses an overlapping, embedded, and moving grid approach to facilitate the flow simulation of arbitrary translationally and rotationally complex geometries among various computational blocks. The domain communication module is fully parallel and is ideally suited for handling moving body problems. To demonstrate the capacities of the method, several sets of example computations are performed and presented in this paper.