Viscous Free-Surface Power Predictions For Self-Propulsion Using A Hybrid RANS-BEM Coupling Procedure (PARNASSOS-PROCAL)

This paper presents results of computations for the 2015 CFD workshop in Tokyo. It briefly describes the RANS method used, the particular treatment of the free surface boundary conditions, and the coupling between the steady RANS code and a boundary element method used for the propeller analysis. Computations for the KCS (case 2.5) have been performed at five grids with different densities. It will be shown that mesh dependence of thrust, torque and RPM at the finest meshes is small, with comparison errors of approximately -0.3 per cent for the resistance, -1.8 per cent for RPM, +3.5 for KT and +5.9 per cent for K _Q. The corresponding error estimation results in uncertainties of less than 1 per cent for the powering parameters, but this value may be too optimistic as a result on at least one more grid has to be generated to perform the uncertainty estimation correctly.