Approaches for performance prediction of marine propellers under open water test conditions using the boundary element method

Open water test predictions with boundary element meth- ods suffer from the fact, that the predicted thrust and torque coefficient at low advance ratios are often not well pre- dicted. This is mainly explained by the missing viscous influence in potential flow theory. Additionally, the accurate computation of surface gradients needed for the pressure distribution is challenging for highly skewed panels. Therefore, in this paper, different approaches are investigated for two representative propellers openly available in the research community; the INSEAN E779A propeller and the Potsdam Propeller Test Case (PPTC). The focus lies in the study, how an unstructured grid with optional consideration of the propeller hub geometry can improve the open water characteristics. First, the chosen mesh topology is described, followed by an assessment of different surface gradient reconstruction approaches for the structured and unstructured grid. Then, open water simulations for different structured and unstructured grids are carried out and the influence of the linear and the nonlinear Kutta condition is discussed on the overall open water characteristics as well as on the pressure distribution in detail. A summary and an outlook is given regarding the capabilities and limitations of unstructured grids and suggestions for further improvements.

Schlagworte

boundary element method

marine propeller

mesh topology

surface gradient

nonlinear Kutta condition

DDC Class

620: Engineering

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Beckmann-ApproachesForPerformancePredictionOfMarinePropellersUnderOpenWat-1201-1-final.pdf

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Approaches for performance prediction of marine propellers under open water test conditions using the boundary element method