A Study on Performance and Cavitation of Propellers for High Speed Crafts Including Effect of Boss

Abstract

For high speed crafts it is often necessary that the propeller be operated under inclined flow conditions. This results in generation of cloud cavitation in the root region leading to erosion. Therefore it is thought necessary that the effect of boss be taken into account in such a case. In the present report as a first step in analysing this problem, the effect of boss in uniform flow was studied. In the theory based on Vortex Lattice Method the boss was represented by a series of source rings the strengths of which were determined from tangency condition on the boss surface. Experiments were performed to measure the pressure distribution on the blade near the root region and also on the boss surface. Theoretical results had been found to agree well with the experimental ones.