Unsteady Propeller Loading--Measurement, Correlation With Theory, and Parametric Study

Periodic single-blade loads on propellers in tangential and longitudinal wakes / by Robert J. Boswell, Stuart D. Jessup, Ki-Han Kim

“…Each of these sets of experimental results show that K(Fx) 1 decreases substantially with increasing J. Figure 8 compares the variation in *(Fx)l with J obtained in the present experiment behind the wake screen with the blade frequency *jFx)n obtained in previous experiments in which the unsteady bearing forces were measured in longitudinal wakes produced by screens in a closedjet water tunnel (17,18,19).…”

Design, Cavitation Performance, and Open-Water Performance of a Series of Research Skewed Propellers

“…That investigation indicated appreciable benefits from the use of blade skew, e.g., substantial reductions in propeller force and moment fluctuations 1 and improved tolerance to the inception of cavitation caused by fluctuations in angle of attack due to operation in a wake. 2 Since there was no deterioration in propulsion characteristics, i.e., efficiency and thrust and torque breakdown due to cavitation, it appeared feasible to consider the use of propeller blade skew as a method of improving propeller cavitation erosion and vibration characteristics without handicapping powering performance.…”

Structural and Acoustic Responses of a Fluid Loaded Shell Due to Propeller Forces

“…To demonstrate the proposed technique, a simplified situation has been considered. A five bladed propeller with zero skew and zero rake (propeller 4381 from Boswell (1971)) is used with the non-uniform inflow represented by a four-cycle wake characterised in water tunnel tests by Boswell and Miller (1968). This four-cycle wake inflow field consists of eight sectors with higher than average velocities on four alternate sectors and lower on the others with approximately +/− 25% maximum variation.…”