Computational Analysis of Marine-Propeller Performance Using Transition-Sensitive Turbulence Modeling

Abstract

Almost all computational fluid dynamics (CFD) simulations of flow around marine propellers use turbulence models that are only well suited for fully turbulent flows, which in some cases may lead to accuracy degradation in the prediction of propeller performance characteristics. The discrepancy between computed thrust and torque and corresponding experimental data increases with increasing propeller load. This is due in part to the fact that a large laminar flow region is found to exist and turbulence transition takes place on propeller blades of model scale and/or under high-load conditions. In these cases, it may be necessary to consider boundary-layer transition to obtain accurate results from CFD simulations. The objective of this work is to perform simulations of a marine propeller using a transition-sensitive turbulence model to better resolve the propeller flow characteristics. Fully turbulent flow simulations are also performed for comparison purposes at various propeller load conditions. Computational results are analyzed and compared with water-tunnel and open-water experimental data. It is found that the applied transition-sensitive turbulence model is better able to resolve blade-surface stresses, flow separations, and tip-vortex originations, and, consequently, improve the prediction accuracy in propeller performance, especially under high-load conditions. Furthermore, solutions obtained using the transition-sensitive turbulence model show tip-vortex flows of higher strength, whereas results by the standard k-ω SST turbulence model indicate excessive dissipation of the vortex core.