Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades

Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades

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Unformatted text preview: International Journal of Rotating Machinery , 9: 263277, 2003 Copyright c Taylor & Francis Inc. ISSN: 1023-621X DOI: 10.1080/10236210390203008 Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades Spyros A. Kinnas, HanSeong Lee, and Yin L. Young Ocean Engineering Group, Department of Civil Engineering, University of Texas at Austin, Austin, Texas, USA Unsteady sheet cavitation is very common on marine propulsor blades. The authors summarize a lifting-surface and a surface-panel model to solve for the unsteady cavitat- ing flow around a propeller that is subject to nonaxisymmet- ric inflow. The time-dependent extent and thickness of the cavity were determined by using an iterative method. The cavity detachment was determined by applying the smooth detachment criterion in an iterative manner. A nonzero- radius developed vortex cavity model was utilized at the tip of the blade, and the trailing wake geometry was determined using a fully unsteady wake-alignment process. Compar- isons of predictions by the two models and measurements from several experiments are given. Keywords Boundary element method (BEM), Unsteady sheet cavi- tation, Unsteady wake alignment A vortex-lattice method (VLM) was introduced for the anal- ysis of fully wetted propeller flows by Kerwin and Lee (1978). The method was later extended to treat unsteady sheet cavitat- ing flows by Lee (1979) and Breslin and colleagues (1982). In Kinnas (1991), a leading-edge correction was introduced to ac- count for the defect of the linear cavity solution near a round Received 25 June 2002; accepted 1 July 2002. Support for this research was provided by Phase III of the Univer- sity/Navy/Industry Consortium on Cavitation Performance of High- Speed Propulsors, which is supported by the following companies and research centers: AB Volvo Penta, American Bureau of Ship- ping, El Pardo Model Basin, Hyundai Maritime Research Institute, Kamewa AB, Michigan Wheel Corporation, Naval Surface War- fare Center Carderock Division, Office of Naval Research (Contract N000140110225), Ulstein Propellers AS, Virginia Tech, Escher Wyss, and Wartsila Propulsion. Address correspondence to Spyros A. Kinnas, Department of Civil Engineering, University of Texas at Austin, Austin, TX 78712, USA. E-mail: kinnas@mail.utexas.edu leading edge. The VLM with the leading-edge correction was incorporated into a code named PUF-3A by Kerwin and col- leagues (1986). Vortex and source lattices were placed on the mean camber surface of the blade, and a robust arrangement of singularities and control-point spacings was employed to pro- duce accurate results (Kinnas and Fine, 1989). The method was then extended to treat supercavitating propellers subjected to steady flow (Kudo and Kinnas, 1995). Recently, the method has been renamed MPUF-3A for its added ability to search for midchord cavitation (Kinnas et al., 1998). The latest version of MPUF-3A also includes the effect of hub, wake alignment in circumferentially averaged inflow with an arbitrary shaft inclina-...
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Modeling of Unsteady Sheet Cavitation on Marine Propeller Blades

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