A Panel Method for the Analysis of the Flow Around Highly Skewed Propellers

Abstract

The present work is concerned with the performance of panel methods when applied to the analysis of the flow around highly skewed propellers. A potential-based low-order panel method, which discretizes the propeller surface with planar quadrilateral panels, has been applied to analyze the flow around a propeller with extreme geometries. The results are much less satisfactory than for conventional geometries. It is then demonstrated that hyperboloidal panels improve the performance of the method substantially. A grid oriented along constant radii generates panels with high aspect ratio and high skewness near the propeller tip, which results in inaccurate calculations of velocities. A "blade orthogonal grid" is developed to solve this problem. Improvements are obtained with this gridding scheme. A linear relationship has been found to exist between thickness and circulation distribution for hydrofoils and propellers. A consistency test is imposed by applying this linear relationship to compare the results of the panel method and a lifting surface method. Finally, the improved propeller panel method is tested for convergence, and compared to other methods.