Computational Analysis of Submarine Propeller Hydrodynamics and Validation Against Experimental measurement

The hydrodynamic performance of a submarine propeller is critical to its operational capability. A well-designed propeller provides optimum speed and endurance and with minimum vibration and acoustic emission. Within DSTO, there exists an ongoing research program which addresses the modeling of submarine hydrodynamic performance using both computational and experimental techniques. Together with the University of Tasmania (Australian Maritime College) and industry, DSTO has been undertaking detailed open-water studies of submarine propellers. This paper describes CFD calculations of a generic seven-bladed propeller which were performed over a range of advance numbers using the commercially-available CFD codes: CFX 11.0 and FLUENT 6.3.26. The results of these calculations were subsequently validated against propeller curves obtained from experimental measurements of the propeller made in the Tom Fink cavitation tunnel at the Australian Maritime College. The calculated thrust and torque were found to be in good agreement with the experimental measurements over the range J=[0.5-0.9], with thrust and torque predicted by both codes being within 4% and 5% of the measurements, respectively. The relative difference between the CFD calculations and experimental measurement increased for larger advance numbers. The CFX results for thrust and torque were found to be in closest overall agreement with the experimental measurements over the range of advance numbers calculated, whereas FLUENT provided the closest overall agreement for open water efficiency. The propeller slipstream appeared to be well resolved close to the propeller where the mesh provided good resolution of the flow field. However the slipstream circumferentially mixed out whilst retaining a distinct radial variation. This may be attributed to a combination of mesh resolution and turbulence modelling. Future research will provide experimental measurements with which to validate the slipstream.