Theoretical investigation of the wake duct effectiveness

The effectiveness of cylindrical and elliptical wake ducts was investigated by using the theoretical methods. The method of surface vorticity distribution was applied to determine the velocity and pressure distributions on the surface of wake ducts in non-uniform stern flow. This method accounts for actual geometry of duct and hull surface with no simplifications. Velocity distribution at meridional sections of a duct was used in calculation of boundary layer parameters in accordance with the Turckenbrodt method. Relative effectiveness of different ducts was evaluated for a specific ship on the basis of the generated thrust and extent of flow separation.