On a propulsion prediction procedure for ships with podded propulsors using RANS-Code analysis

The paper presents an analysis of calculations made with RANS codes for propulsion pod housings at model and full-scale Reynolds numbers. The authors consider two podded unit configurations: a streamlined body and a body with a blunt downstream edge. The performed analysis demonstrates that specific features of the flow around podded propulsors make resistance scaling techniques based on the form factor inapplicable. It is suggested to render the pod housing drag non-dimensional like it is done for the propeller thrust coefficient and to extrapolate it with the help of scale factors found from RANS computations for the model and the full-scale Reynolds numbers. For the considered podded unit configurations, this scale factor is in a range of 0.7 for the streamlined option to 0.86 for the blunt-edge on