Estimation of the Induced Hydrodynamic Periodic Forces of Marine Propeller under Non-Uniform Inflow via CFD

Abstract

In this work, both steady and unsteady Reynolds-Averaged Navier Stokes (RANS) simulations have been used via FLUENT software to calculate the induced 3-D hydrodynamic forces and moments of marine propeller. Marine propeller is excited by variation of hydrodynamic loading due to its operation in non-uniform wake field. The induced hydrodynamic forces and moments are calculated for single blade and for all blades at low Reynolds number under two operating conditions. The first one, uniform inflow is considered at the inlet. The second one, non-uniform inflow is considered at the inlet (under the wake effect of the ship) to represent the propeller-ship interaction. Unsteady results show that, due to non-uniform inflow every single blade is suffering from periodic forces and moments with fluctuation amplitude and harmonies higher than that applied on the propeller shaft but with lower frequency. The moments in vertical and transversal directions My and Mz are higher than the axial moment Mx. This study shows that, using Computational Fluid Dynamics (CFD) to solve RANS equation is a reliable tool for calculating the hydrodynamic characteristics and estimating the excited hydrodynamic forces due to propeller-ship interaction.