NUMERICAL SIMULATION OF THE FLOW AROUND SHIPS IN CALM SEA AND IN REGULAR HEAD WAVES BY USING WAVIS CODE

Abstract

The paper describes the feasibility study on numerical towing tank applications for Tokyo 2015 CFD workshop. The first application is Reynolds Averaged Navier-Stokes (RANS) equation based simulation to predict the performances of resistance and self-propulsion performances for the Japan Bulk Carrier (JBC) with and without a stern duct. The second is unsteady RANS (URANS) simulation to predict the sea keeping performances of added resistance, heave and pitch motions for KRISOContainer ship (KCS) advancing in regular head waves. The numerical grids are generated as three geometrically similar grid systems - coarse, medium, fine grids for the verification and validation (V&V) analysis of JBC. The grid of KCS in waves is sufficiently distributed in the longitudinal direction and near the free surface area to resolve the incoming and scattered waves. The numerical results are obtained using WAVIS code developed by KRISO, which uses a cell-centered finite volume method for the discretization of the governing equations. The free surface is captured using a two-phase level-set method and the realizable k-ε model and the Explicit Algebraic Stress Model (EARSM) are used for turbulence closure. The propeller effect is considered as body force obtained from unsteady lifting surface method for the simulation of self-propulsion condition. In the case of KCS advancing in regular head waves, Two degrees of freedom motion (pitch a and self-propulsion performances for the Japan Bulk Carrier (JBC) with and without a stern duct. The second is unsteady RANS (URANS) simulation to predict the sea keeping performances of added resistance, heave and pitch motions for KRISOContainer ship (KCS) advancing in regular head waves. The numerical grids are generated as three geometrically similar grid systems - coarse, medium, fine grids for the verification and validation (V&V) analysis of JBC. The grid of KCS in waves is sufficiently distributed in the longitudinal direction and near the free surface area to resolve the incoming and scattered waves. The numerical results are obtained using WAVIS code developed by KRISO, which uses a cell-centered finite volume method for the discretization of the governing equations. The free surface is captured using a two-phase level-set method and the realizable k-ε model and the Explicit Algebraic Stress Model (EARSM) are used for turbulence closure. The propeller effect is considered as body force obtained from unsteady lifting surface method for the simulation of self-propulsion condition. In the case of KCS advancing in regular head waves, Two degrees of freedom motion (pitch a