FEASIBILITY STUDY ON NUMERICAL TOWING TANK APPLICATION TO PREDICTIONS OF RESISTANCE AND SELF-PROPULSION PERFORMANCES FOR A SHIP

Abstract

RANS(Reynolds-Averaged Navier-Stokes) equation based simulations are performed to predict the performances of resistance and self-propulsion characteristics for the KRISO VLCC Tanker (KVLCC2) and KRISO Container Ship (KCS) including sinkage and trim. All numerical grids are generated with own developed grid generator starting from 2D offset table of the hull forms. The numerical results are obtained using a RANS based general ship hydrodynamic code, WAVIS that 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 a realizable k-ε model is used for turbulence closure. The sinkage and trim are computed at one computational time step and applied in the succeeding time step through treatment in the non-inertial reference frame, which is performed with an interval of a fifth to tenth of the total number of iteration for simulation. The propeller effect is considered as body force obtained from unsteady lifting surface method for the simulation of self-propulsion condition. The verification and validation (V&V) analysis is applied to the total resistance coefficient as an integral variable for both fixed and free condition. For KVLCC2 and KCS model ships, computational errors are less than validation uncertainties such that the obtained numerical results are validated at the level of validation uncertainty 1.005~1.326%D. For KCS self-propulsion condition, since the data uncertainty was not given, only verification analysis is performed for the total resistance, thrust, torque, and rps. The simulation based self-propulsion factors are in good agreement with experimental results. The present study can lead to the following conclusion such that developed RANS based simulation for towing and self-propelled model ship is promising to be used as a tool for hull form designers.