On the simultaneous design of blade and duct geometry of marine ducted propulsors

In ducted propulsor design for marine vessels, due to the strong interactio n between the duct and the propeller blades, it is very important to design the duct and the blade geometry simultaneously. Here, a three-dimensional inverse design method is presented to take this into consideration. The met hod is based on three-dimensional potential flow; however. the effect of th e inlet shear flow and the resulting rotational flow is also modeled via th e Clebsch formulation. The duct profile is designed to achieve a target vel ocity distribution while the blade geometry is computed to attain a desired mass-flow rate and a certain circulation distribution. The method is appli ed to the design of three generic ducted propulsors with a 7-bladed contrar otating configuration.