Effect of Operational Conditions on the Cavitation Inception Speed of Naval Propellers
Author Terwisga, T.J.C. van, Noble, D.J., Veer, R. van’t, Assenberg, F., McNeice, B. and Terwisga, P.F. van
Title Effect of Operational Conditions on the Cavitation Inception Speed of Naval Propellers
Conference/Journal 25th Symposium on Naval Hydrodynamics, St. John's, Canada
Month August
Year 2004

A propeller analysis package for time domain simulations is described that permits evaluation of the effects of variable operating conditions on propeller cavitation inception in a seaway. The package is based on linear seakeeping and propeller lifting surface theories and is combined with a simulator that models the dynamic response of conventional twin propeller and ship engine systems. It is developed in a cooperative project by the Canadian, Netherlands and Australian Navies and MARIN. In this paper, the simulation tool is applied to a representative naval ship and propeller design to illustrate the effect of sea state, heading and propeller control strategy on the cavitation inception speed.
In the sample case examined, the effect of sea state on cavitation inception speed in bow quartering seas is shown to agree with previous full-scale observations and measurements, predicting a cavitation inception speed in sea state 6 of only some 36% of that in sea state 2. A range of propeller control strategies is examined to show that operating propellers using a constant thrust coefficient and ship speed control strategy can produce a cavitation inception speed that is some 29% higher in following seas at sea state 4 than obtained with a commonly used propeller shaft speed control algorithm. For bow quartering waves in the same sea state, no significant difference in inception performance could be found using the same controller settings. Optimization of the controller for each direction to waves is likely to improve inception speeds for headings other than following seas as well.

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