Numerical Modeling of Propeller Tip Flows with Wake Sheet Roll-up in ThreeDimensions

摘要

A boundary element method is applied to the prediction of the flow aroundpropeller blades, with emphasis at the tip region. The presented work is divided into three major parts. In the first part, a new panel arrangement, namely the FLow Adapted Grid (FLAG), is proposed. This grid is normal to the blade leading edge outline and adjusted to the force free wake geometry at the trailing edge. The location of the tip vortex detachment point is determined by an iterative method. The effectiveness and robustness of the flow adapted grid are demonstrated through numerical validation tests and through comparisons with existing experiments. The flow adapted grid is found to improve: (a) the predicted velocity flow field and the pressure distribution at the tip, (b) the convergence of an iterative pressure Kutta condition, and (c) the overall numerical performance of the method and its consistency to lifting surface theory. The second part addresses an algorithm for predicting the three-dimensional vortex sheet roil-up. A higher order panel method, which combines a