Influence of Turbulence Closures for Wake Prediction for Marine Propeller Design

Results of computational fluid dynamics validation for flow around a marine propeller are presented. Computations were performed for various advance coefficients, following experimental conditions.

The objectives of this study are to establish the capabilities of various turbulent closures to predict the wake of a propeller and to predict the instability processes in the wake.

Two RANS models are used: the k-w SST of Menter and an anisotropic two-equation Explicit Algebraic Reynolds Stress Model (EARSM). A DES approach based on the k-w model is also used. Computational results for both global and local flow quantities are discussed and compared with experimental data.

The predicted thrust and torque are in good agreement with the measured values for all turbulent closures. With the RANS turbulence models, the wake of the propeller is too dissipated and then the instabilities of the wake are not predicted. On the contrary, the DES approach can allow to capture the evolution of the tip vortices and predicts the onset of instabilities in the wake.

The main difference between these various turbulence closures is that the flow in the core of the vortex is characterized by rotation, streamline curvature effects which are not adequately modeled by RANS turbulence models.

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Posted by Benoit Mallol

Benoit holds a master's degree in Mechanical and Numerical modeling from the University of Bordeaux (France) with a specialization in CFD dedicated to free surface flows. For more than 10 years, he has been working on unstructured meshing strategies and marine applications. As head of the marine group and head of the unstructured meshing group, Benoit drives the product roadmaps, acts as the CFD technical expert to support all our offices around the world, and makes sure that the software remains the reference on the different markets.