An improved analysis methodology for the prediction of steady propulsor performance

A modern vortex-lattice lifting-surface propeller blade design (PBD) code is coupled with a multi-element streamline curvature throughflow solver to efficiently analyze a marine propulsor in the presence of a rotational inflow. In this loosely coupled technique, the propeller design program predicts propeller blade forces based on an assumed inflow velocity. These forces are then input into the streamline curvature program which computes a new total inflow velocity field. The updated effective inflow velocity, field is returned to the propeller design program, and new blade forces are computed. Convergence is achieved usually after five or six loosely coupled iterations. The original researchers who developed this loosely coupled propeller design methodology relied upon Reynolds-Averaged Navier-Stokes (RANS) throughflow solvers to compute the throughflow solution: The use of a streamline curvature code results in an order-of-magnitude reduction in the computational time required by the flow solver, and allows nearer real-time design and analysis. Preliminary validation results show good agreement with both empirical and numerical tests.