Experimental Evaluation of a Series of Skewed Propellers with Forward Rake:Open-Water Performance,Cavitation Performance,Field-Point Pressures,and Unsteady Propeller Loading,

摘要

Results are given showing the experimental effect of propeller-blade warp on open-water performance,cavitation performance,unsteady field-point pressures,and unsteady propeller loading for a series of warped propellers. Blade warp is defined as the angular displacement at the midchord point of the blade section from the blade reference line in the plane of rotation. Open-water results indicate that at the design thrust-loading coefficient and shaft horsepower the warped propellers are as much as 4.5percent less than the design rpm. Cavitation results show a widening of the cavitation-free bucket with increasing warp;however,there is some crossover in the inception of back cavitation and tip-vortex cavitation. Field-point pressures and the unsteady propeller forces and moments have been found to decrease with increasing warp to reductions previously achieved with blade skew. (Author)