Partially Cavitating Flows about Foils.
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD
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There is concern with avoiding problems and reducing the likelihood of propeller-induced hull vibration, noise, and blade erosion on Navy ships. The unsteady surface pressure excitation and local flow instability responsible for these problems are associated with blade sheet cavity geometry and cavity dynamics. Reliable computational tools for the analysis of propeller blade sheet cavitation would be useful for assessments of given propellerwakehull arrangements and for guidance of new propeller geometries intended to keep blade cavitation and excitation levels under some control. This report presents a practical approach for predicting partially cavitating flow characteristics of foil sections. The method takes into account indirectly the viscous flow effects and the interaction between the fully wetted and perturbed cavitating flows. The partially cavitating flow characteristics are found to be sensitive to variations in the angle of attack, camber, thickness, and the thickness distribution. Some comparisons between the calculated and measured cavity lengths are made, and the results are generally in good agreement. Keywords Partially cavitating flows Foils Cavity length Cavity volume.
- Marine Engineering
- Fluid Mechanics