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Abstract
The purpose of this thesis is to determine the effectiveness of a stator array placed forward of the propeller in regard to producing a more uniform flow to the propeller. The nominal wake flow abaft the stern is spatially highly nonuniform, i.e., the axial and tangential velocities vary peripherally in a cyclic manner. A radial array of $Z\sb{s}$ stator blades in the spatially nonuniform hull wake produces induced velocities in the plane of the propeller at all spatial frequencies. These induced velocities are parametrically dependent on the stator orientation, that is, upon the angle $\theta$ of a key blade in the stator array. Then, by rotating the stator array, a most favorable $\theta$ can be found to minimize the net flow normal to the propeller blade over a range of radii of importance. Furthermore, an harmonic variation of angle of attack of the stators can be found by minimizing this net normal component. Lifting-line theory is applied to calculate the induced velocities via solution of an integro-differential equation for the unknown stator blade loadings arising from specific hull wake harmonics and also from imposed variations on the stator blade pitch angles. The modulus of the vector sum of the nominal and induced components are then required to satisfy criteria imposed to minimize unsteady blade frequency forces on the propeller shaft. Tentative conclusions are drawn from the numerical results.
