Numerical prediction of flows around podded propulsors

Podded propulsor units are one of the latest innovations in the filed of propulsion, and are used in many commercial and recreational vessels. The major advantage of these units over conventional propeller based system is their ability to provide thrust in all directions, giving high maneuverability and good seakeeping characteristics. Podded propulsors or general geometry are modeled numerically in 3-D and the flow around the propulers, the pod, and the strut is evaluated. A general method of coupling of a Finite Volume Method (FVM) and a Vortex Lattice Method (VLM) is applied. The Euler equations are solved using the FVM, which is applied to model the 3-D flow around the pod with the strut, while the VLM models the flow in the vicinity of the propeller. Iterations are performed between the two methods until the solution converges. The purpose of using the above approach is to determine the effective wake of each component of the propulsor, which is modified due to the presence of the other components, and evaluate its performance subject to this effective inflow velocity. The overall goal of this research is to predict the forces on the whole propeller and pod unit at various angles of attack, by integration of the pressures. The results from the present method are compared with those of other methods, as well as, validated with measurements from experiments.