Improving model scale propeller performance prediction using the k - kL - ω transition model in OpenFOAM

The effect of laminar to turbulent flow transition plays an important role for the prediction of model scale performance, which is of utmost interest for the development of scaling approaches entirely based on Computational Fluid Dynamics calculations. The recent inclusion of transition models (either based on local correlations, like the γ - Re θ, or on the concept of kinetic laminar energy, like the k - k L - ω) in many RANS codes fosters their application for improving the model scale prediction of propeller performance. In the present work the numerical results using the well-established SST k - ω and the k - k L - ω turbulence models available in OpenFOAM are presented and compared with towing tank experiments for three test case propellers. The influence of turbulence parameters (i.e. turbulence intensity and turbulent viscosity ratio at inlet) is discussed, at first for the ERCOFTAC T3A flat plate validation case, through which useful guidelines for propeller performance predictions using transition sensitive turbulence models are derived. By using these relationships, a significant improvement of numerical predictions of propeller forces is achieved, with discrepancies with respect to model scale measurements appreciably reduced if compared to usual fully turbulent calculations. At the same time the limitations of the adopted transitional model are discussed based on the systematic analyses carried out for three test cases.