Methods for Cavitation Prediction on Tip-Modified Propellers in Ship Wake Fields

Unsteady cavitation simulations on a tip-modified propellerin behind-hull condition are made by both BoundaryElement Method (BEM) and Computational FluidDynamics (CFD).As the hull geometry typically is not disclosed to thepropeller designer and thus cannot be included in thesimulation, other measures must be taken to account for theship’s wake field. In CFD, different wake models using anon-uniform inlet flow and momentum sources are tested toachieve resulting axial and transverse flows in the propellerplane that resemble the desired wake field.Also, the simulations are carried out with two types of hullwake fields: One originating from model test measurementsand the other from a bare hull RANS simulation at thecavitation test Reynolds number. By comparing simulationresults, the different numerical approaches are evaluated foraccuracy of the unsteady cavitation prediction as a propellerdesign tool complementing the cavitation tunnel test.