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 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, 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 modelled by RANS turbulence models.
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