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.