Numerical simulation of boundary-layer transition flow of a model propeller and the full-scale propeller for studying scale effects

Abstract

Propeller scale effects were widely studied from boundary-layer flow, friction and pressure distributions, propeller performance and tip vortices. The γ-Reθ transition model and two turbulence models (STAR-CCM+) were applied for the model propeller simulation, and the influence of turbulence intensity on the boundary-layer flow was studied. The transition model was also applied for the full-scale propeller simulation, and numerical results were compared with that predicted by a commonly used turbulence model. Data from open water tests and velocity measurements of the model propeller were used for validation. Results show that scale effects of propeller performance are mainly caused by different boundary-layer flows: the boundary-layer flow of the full-scale propeller is basically turbulent, while the flows over the blade face and blade back of the model propeller are complex, different and sensitive to the Reynolds number. By studying the effect of varying Reynolds numbers on propeller performance, boundary-layer flow and tip vortices, why the Reynolds number of the model propeller in experiments needs to be greater than the critical Reynolds number was studied. Last, scale effects and propeller performance of the full-scale propeller predicted by numerical methods and the ITTC recommended scaling method are close.