An Experimental and Theoretical Study on Cavitating Propellers.
Technical rept. 1 Nov 80-31 Oct 82,
TETRA TECH INC PASADENA CA
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The original objective of the present work was to develop an analytical tool for predicting the off-design performance of supercavitating propellers over a wide range of operating conditions. Due to the complex nature of the flow phenomena, a lifting line theory simply combined with the two-dimensional supercavitating cascade theory was selected. Results of this simple method provided surprisingly accurate predictions for the performance at fully developed cavitating conditions. It was indicative that the fully-developed, supercavitating propellers had strong cascade effects on their performance, and also that the three-dimensional, propeller geometry corrections could properly be made by the lifting-line theory. As was expected, however, the predicted thrust and power coefficient curves with this propeller theory showed a significant deviation from experimental data in the range of advance speeds Js larger than designed advance speeds where the partially cavitating conditions are expected to occur. effort was then made to improve the prediction capability of the above propeller theory at partially cavitating conditions. A new nonlinear partially cavitating cascade theory was developed to provide a proper 2-D loading basis under such conditions. A slight improvement on the prediction capability of the propeller theory was achieved with the new set of data, but not to a satisfactory extent.
- Marine Engineering
- Fluid Mechanics