Application of a Boundary Element Method in the Prediction of Unsteady Blade Sheet and Developed Tip Vortex Cavitation on Marine Propellers

Abstract

Most marine propellers operate in nonaxisymmetric inflows, and thus their blades are often subject to an unsteady flow field. In recent years, due to increasing demands for faster and larger displacement ships, the presence of blade sheet and tip vortex cavitation has become very common. Developed tip vortex cavitation, which often appears together with blade sheet cavitation, is known to be one of the main sources of propeller-induced pressure fluctuations on the ship hull. The prediction of developed tip vortex cavity as well as blade sheet cavity is thus quite important in the assessment of the propeller performance and the corresponding pressure fluctuations on the ship hull. A boundary element method is employed to model the fully unsteady blade sheet (partial or supercavitating) and developed tip vortex cavitation on propeller blades. The extent and size of the cavity is determined by satisfying both the dynamic and the kinematic boundary conditions on the cavity surface. The numerical behavior of the method is investigated for a two-dimensional tip vortex cavity, a three-dimensional hydrofoil, and a marine propeller subjected to nonaxisymmetric inflow. Comparisons of numerical predictions with experimental measurements are presented.

Predicting the cavitating marine propeller noise at design stage: A deep learning based approach

“…The pioneering applications of BEM for the characterization of propellers performances were those by [33][34][35][36] which progressively extended BEM capabilities to unsteady and cavitating flows also in the case of unconventional propellers like ducted propulsors. Midchord cavitation detachment, approximated tip vortex cavitation and the possibility to deal with supercavitating hydrofoils and propellers were included by [37,38] and [39], while extensive validation against cavi-tation tunnel measurements were provided by [40], [41] and [42].…”

A 3-D Viscous Vorticity Model for Predicting Turbulent Flows over Hydrofoils

“…PROPCAV enabled the analysis of unsteady cavitating flow around propellers under nonaxisymmetric inflow conditions [9,10]. This approach expanded to encompass various complexities, including noncylindrical propeller bosses, midchord cavitation on either side of the blade, surface-piercing propellers [11][12][13], unsteady tip vortex cavitation [14], and fully unsteady trailing wake alignment [15]. Du and Kinnas [16] developed a 3-D flow separation model for open propellers with a blunt trailing edge.…”

An alternative Vorticity based Adaptive Mesh Refinement (V-AMR) technique for tip vortex cavitation modelling of propellers using CFD methods

“…lifting surface and panel methods) are generally used in the propellers' early design stage to account for the sheet cavitation and its effects on the propeller hydrodynamic performance (e.g. Fine and Kinnas 1993;Lee and Kinnas 2004). However, the potential flow solvers may have some drawbacks for accurate predicting the cavitation dynamics compared to viscous flow solvers.…”