Numerical modelling of unsteady hydrodynamic characteristics of a propeller-rudder configuration

A theoretical model for the hydrodynamic analysis of a propeller­rudder configuration is presented. The methodology is based on a boundary integral formulation for the velocity potential and is valid for unsteady inviscid flows. The propeller slipstream is studied by using a wake alignment technique, and cavitating flow on both propeller blades and on rudder is predicted by means of sheet cavitation modelling. A fully unsteady time accurate solution procedure is derived in order to describe the transient flow around the rudder in the propeller wake. Some preliminary numerical results are presented to demonstrate the capability of the proposed methodology to describe the flowfield downstream an isolated propeller and to predict cavitation patterns on propeller blades and on rudders in uniform inflow.