Enhancement of Navier-Stokes solver based on an improved volume-of-fluid method for complex interfacial-flow simulations

In this study, an extended validation of an improved volume-of-fluid (VOF)-based method for 3D highly nonlinear, complex, and breaking free-surface problems in engineering is presented. The VOF interface-tracking scheme is implemented with a Navier-Stokes solver in a curvilinear coordinate system. The numerical procedure is advanced by implementing the scheme on moving Chimera (overset) grids for application in complex engineering problems. The overset grids are used to facilitate the flow simulations of complex geometries and arbitrary motions of objects and improve computational productivity by taking advantage of their flexibility. To solve the six degrees of freedom (6DOF) motions of a rigid body simultaneously, the nonlinear 6DOF motion equations in a vector form system are strongly combined with a flow solver. A collection of problems is carefully selected such that a large density ratio and complex cases under a wide variety of Froude numbers are presented with the aim of demonstrating the capabilities of the new enhanced method on a complicated moving overset grid system. The method is validated for a wide range of parameters. The results of different free-surface problems are presented. The numerical results are compared with numerical alternatives and experimental measurements, and accurate approximations and good agreement are obtained for complex flows.