A BEM for the Prediction of Unsteady Midchord Face and/or Back Propeller Cavitation

A boundary element method (BEM) is used for the numerical analysis of sheet cavitation on a propeller subjected to the non-axisymmetric wakes of marine vehicles. This method is extended in order to treat mixed partial and supercavity patterns on both the face and back of the blades with searched cavity detachment. The convergence of the method is studied. The predicted cavity shapes and forces by the present method agree well with experiments and with those predicted by another numerical method.

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Boundary Element Method Used in Random Response Calculation of the Plate-Beam Structure

13th Biennial Conference on Mechanical Vibration and Noise: Vibration Analysis — Analytical and Computational ◽

10.1115/detc1991-0344 ◽

1991 ◽

Author(s):

J. M. Zhu ◽

L. Huang

Keyword(s):

Boundary Element Method ◽

Numerical Method ◽

Boundary Element ◽

Pressure Fluctuation ◽

Random Vibration ◽

Power Plants ◽

Measured Data ◽

Random Response ◽

Beam Structure ◽

Element Method

Abstract The furnace walls of the large boilers in power plants are combined structures consisting of orthotopic plate and equally spaced beams, which are usually submitted to random vibration under the excitation of the pressure fluctuation induced by combustion in the furnace. In this paper, a numerical method based on BEM to compute the random response of the structure is offered. The agreement between the computing results and the measured data in a practical example verifies the effectiveness of the method.

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

Journal of Ship Research ◽

10.5957/jsr.2004.48.1.15 ◽

2004 ◽

Vol 48 (01) ◽

pp. 15-30

Author(s):

Hanseong Lee ◽

Spyros A. Kinnas

Keyword(s):

Boundary Element Method ◽

Boundary Element ◽

Pressure Fluctuations ◽

Ship Hull ◽

Tip Vortex ◽

Tip Vortex Cavitation ◽

Marine Propellers ◽

Sheet Cavitation ◽

Numerical Predictions ◽

Element Method

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.

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Application of hybrid boundary element method: Example of semishperical ground inhomogeneity

Serbian Journal of Electrical Engineering ◽

10.2298/sjee1404617c ◽

2014 ◽

Vol 11 (4) ◽

pp. 617-628

Author(s):

Nenad Cvetkovic ◽

Sasa Ilic ◽

Dragan Vuckovic ◽

Dejan Jovanovic ◽

Dejan Krstic

Keyword(s):

Boundary Element Method ◽

Point Source ◽

Numerical Method ◽

Boundary Element ◽

Program Package ◽

Image Theory ◽

Field Analysis ◽

Grounding System ◽

Em Field ◽

Element Method

One new, so-called hybrid boundary element method (HBEM) is presented in this paper. It is a recently proposed numerical method for stationary and quasi-stationary EM field analysis. The method application is illustrated on the example of solving the problem of modelling hemispherical ground inhomogeneity influence on grounding system. The applied procedure also includes using of quasi-stationary image-theory. The obtained results are compared with those ones based on using the Green?s function for the point source inside semi-spherical inhomogeneities as well as with the results obtained by applying COMSOL program package.

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