Numerical simulation of diffracted wave by a vertical cylinder using VOF method

Abstract

In this paper, numerical simulations of diffracted wave around bottom-mounted circular cylinder are presented using volume-of-fluid (VOF) method. Unsteady incompressible Navier-Stokes equations are solved based on finite volume method (FVM) with collocated variable arrangement. SIMPLE-type correction algorithm with momentum interpolation method is applied to solve pressure-poisson equations. Among many variations of VOF method, CICSAM (Compressive Interface Capturing Scheme for Arbitrary Meshes) scheme is adopted. To verify the availability in two-phase flow simualtions of the developed numerical code, dam-breaking and sloshing problems are investigated. The simulation results show good agreement in both flow pattern and global force with existing experiments. Before the numerical simulation of three-dimensional diffraction problems, wave is tested in numerical wave tank. In present study, we introduce a buffer zone for efficient wave-making and damping. In the buffer zone, the near field solution is gradually changed to the known incident wave at the far field. Second-order Stokes waves are well simulated in present wave tank. Finally, diffracted wave by vertical circular cylinders is numerically simulated. The wave-induced forces and run-ups around cylinder are compared with potential solutions based on finite-element method (FEM). Agreement between two numerical solutions is fairly good. ？ 2010 by The International Society of Offshore and Polar Engineers (ISOPE).