Improved wake model of a new type of POD propulsion

To improve the precision of a numeric calculation method for the hydrodynamic performance of a POD propulsion system, a propeller wake model was developed. To investigate the influences of several key parameters of the wake model on the predicted propeller performance, extensive numerical computation was carried out by changing parameter values. With the wake geometry calculated by a simplified wake alignment method, the interrelation of the hydrodynamic pitch with the geometrical pitch and the inflow pitch was analyzed so that a model for the interrelation was derived, and then the coefficients in the model were determined. An improved trailing vortex wake model for podded propulsor was developed. Real-case calculation was carried out to verify the validity and applicability of this new wake model, in which two different podded propellers were used. Test data and computation results were also compared using the old wake model. It is shown that this new wake model has greater precision than the old wake model and also enjoys good applicability.