| High speed marine vehicle propulsion requires special propellers. The trochoidal propeller has the potential to perform at high speeds with high hydrodynamic efficiency and excellent maneuvering characteristics.; A description of a 3-bladed, 150 millimeter orbit diameter model trochoidal propeller is presented. This model was designed and constructed for experiments in a cavitation tunnel. A preliminary set of tests was done with the model to evaluate its performance. The tests were comprised of forward, reverse, and zero speed propeller operations. Several forward operation tests were done at reduced pressures to investigate the cavitation characteristics of this propeller. All tests covered a range of advance coefficient and measurements were made so that the main propeller performance coefficients, thrust, side force, torque, and efficiency, could be determined.; Multiple streamtube theory is developed to account for the effects of propeller blade pitching, dynamic stall, and work done to oscillate the blades. The predictions made by each of the modifications are compared to the original multiple streamtube theory predictions, and to experimental results. None of the modifications provide reliable estimations of all performance characteristics, but the dynamic stall formulation, when applied to regions of low turbulence, predicts thrust performance more accurately than the other modified theoretical models. |
