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

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.

scholarly journals The Added Mass Coefficient computation of sphere, ellipsoid and marine propellers using Boundary Element Method

2011 ◽  
Vol 18 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Hassan Ghassemi ◽  
Ehsan Yari
Keyword(s):  
Boundary Element Method ◽  
Numerical Methods ◽  
Boundary Element ◽  
Mass Matrix ◽  
Added Mass ◽  
Experimental Results ◽  
Marine Propellers ◽  
Mass Coefficient ◽  
Added Mass Coefficient ◽  
Element Method

The Added Mass Coefficient computation of sphere, ellipsoid and marine propellers using Boundary Element Method Added mass is an important and effective dynamic coefficient in accelerating, non uniform motion as a result of fluid accelerating around a body. It plays an important role, especially in vessel roll motion, control parameters as well as in analyzing the local and global vibration of a vessel and its parts like propellers and rudders. In this article, calculating the Added Mass Coefficient has been examined for a sphere, ellipsoid, marine propeller and hydrofoil; using numerical Boundary Element Method. Since an Ellipsoid and a sphere have simple geometric shapes and the Analytical values of their added mass coefficients are available, so that the results of added mass matrix are obtained and evaluated, using the boundary element method. Then the added mass matrix is computed in a given geometrical and flow specifications for a specific propeller and its results are studied versus experimental results, which it's current numerical data In comparison with other numerical methods has a good conformity with experimental results. The most important advantage of the method in determining the added mass matrix coefficients for the surface and underwater vessels and the marine propellers is extracting all the added mass coefficients with very good Accuracy, while in other numerical methods it is impossible to extract all the coefficients with the Desired Accuracy.

Prediction of Sheet Cavitation on Marine Current Turbines With a Boundary Element Method

2012 ◽  
Author(s):  
J. Baltazar ◽  
J. A. C. Falcão de Campos
Keyword(s):  
Boundary Element Method ◽  
Boundary Conditions ◽  
Boundary Element ◽  
Design Stage ◽  
Sheet Cavitation ◽  
Operation Conditions ◽  
Marine Current Turbine ◽  
Marine Current ◽  
Current Turbine ◽  
Element Method

For marine current turbines under certain operation conditions cavitation on the blades may occur. Therefore, it is important from the design stage of such systems to be able to predict the presence and extent of cavitation on the blades. In this paper a boundary element method for the prediction of sheet cavitation of a horizontal axis marine current turbine is presented. The boundary element method is based on a low-order potential formulation. Dipoles and sources are placed on the rigid body surfaces either on the wetted part and beneath the cavities. Kinematic boundary conditions are applied on the wetted surfaces and kinematic and dynamic boundary conditions are applied on the surface of the cavities. The blade wakes are modeled with an empirical formulation. The method is applied to analyze a marine current turbine in steady flow conditions and results are compared with the cavitation observations available in the literature.

A Comparison of Different Fluid-Structure Interaction Analysis Techniques for the Marine Propeller

2021 ◽  
Author(s):  
Wajiha Rehman ◽  
Stephane Paboeuf ◽  
Joseph Praful Tomy
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stokes Equations ◽  
Hydrodynamic Performance ◽  
Design Stage ◽  
Cooperative Research ◽  
Design Assessment ◽  
Fluid Structure ◽  
Marine Propellers ◽  
Element Method

Abstract The performance of the propeller is crucial to determine the energy-efficiency of a vessel. Fluid-Structure Interactions (FSI) analysis is one of the widely used methods to determine the hydrodynamic performance of marine propellers. This article is about the validation of a design assessment tool known as ComPropApp which is developed by Cooperative Research Ships (CRS) partners. ComPropApp is a specially designed tool for the FSI analysis of isotropic and composite marine propellers by doing explicit two-way coupling of the BEM-FEM solvers. The Boundary Element Method (BEM) solver of ComPropApp gives it an edge over Reynolds Averaged Navier Stokes Equations (RANSE) solvers in terms of computation time and cost. Hence, it is suitable for the initial design stage. The propeller used in this study is developed under the French Research Project; FabHeli. The validation is done by performing different types of FSI analysis through commercial RANSE solver (STAR-CCM+) and FEM solver (FEMAP) for only one inflow velocity of the open water case which is 10.3 m/s. The fluid solver of ComPropApp (PROCAL) is a Boundary Element Method (BEM) solver that is based on the potential flow theory while the structural solver (TRIDENT) is a FEM solver. The study is divided into four different cases; BEM-FEM one-way coupled FSI analysis, RANSE-FEM one-way coupled FSI analysis, BEM-FEM explicit two-way coupled FSI analysis with ComPropApp and RANSE-FEM implicit two-way coupled FSI analysis with STAR-CCM+. The calculated values of stresses, displacement, and forces from all the methods are compared and the conclusion is drawn.

scholarly journals The singing vortex

2015 ◽  
Vol 5 (5) ◽  
pp. 20150025 ◽  
Author(s):  
R. Arndt ◽  
P. Pennings ◽  
J. Bosschers ◽  
T. van Terwisga
Keyword(s):  
Dynamic Behaviour ◽  
Tip Vortex ◽  
Frequency Content ◽  
Tip Vortex Cavitation ◽  
Marine Propellers ◽  
Sheet Cavitation ◽  
Propeller Design ◽  
Research Article ◽  
Propeller Blades ◽  
Vortex Disturbances

Marine propellers display several forms of cavitation. Of these, propeller-tip vortex cavitation is one of the important factors in propeller design. The dynamic behaviour of the tip vortex is responsible for hull vibration and noise. Thus, cavitation in the vortices trailing from tips of propeller blades has been studied extensively. Under certain circumstances cavitating vortices have been observed to have wave-like disturbances on the surfaces of vapour cores. Intense sound at discrete frequencies can result from a coupling between tip vortex disturbances and oscillating sheet cavitation on the surfaces of the propeller blades. This research article focuses on the dynamics of vortex cavitation and more in particular on the energy and frequency content of the radiated pressures.

Propeller Sheet Cavitation Predictions Using a Panel Method

1999 ◽  
Vol 121 (2) ◽  
pp. 282-288 ◽  
Author(s):  
A. C. Mueller ◽  
S. A. Kinnas
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Panel Method ◽  
Time Dependent ◽  
Variable Pressure ◽  
Water Tunnel ◽  
Sheet Cavitation ◽  
Pressure Water ◽  
Element Method ◽  
Blade Geometry

A boundary element method is used to predict the time-dependent cavitation on a propeller subject to nonaxisymmetric inflow. The convergence of the method is studied. The predicted cavities agree well with those observed in CAPREX, an experiment performed at MIT’s variable pressure water tunnel. The method is modified so that prediction of cavities detaching at mid-chord regions is possible. An algorithm for predicting the cavity detachment location on the blade is described and applied on a blade geometry which exhibits mid-chord cavitation.

Steady cavitating propeller performance by using OpenFOAM, StarCCM+and a boundary element method

2016 ◽  
Vol 231 (2) ◽  
pp. 411-440 ◽  
Author(s):  
Stefano Gaggero ◽  
Diego Villa
Keyword(s):  
Boundary Element Method ◽  
Open Source ◽  
Boundary Element ◽  
Open Water ◽  
Fundamental Aspect ◽  
Test Case ◽  
Numerical Predictions ◽  
Propeller Performance ◽  
Thrust And Torque ◽  
Element Method

Accurate and reliable numerical predictions of propeller performance are a fundamental aspect for any analysis and design of a modern propeller. Prediction of cavitation and of cavity extension is another important task, since cavitation is one of the crucial aspects that influences efficiency in addition to propagated noise and blade vibration and erosion. The validation of the numerical tools that support the design process, including open-source codes, is, consequently, essential. The public availability of measurements and observations which cover not only usual thrust and torque in open water conditions (including cavitation) but also unsteady functioning with pressure pulse measurements in the case of the Potsdam Propeller Test Case certainly represents an extremely useful source of information and an excellent chance for verification and validation purposes. In the present work, the prediction of the Potsdam Propeller Test Case propeller performance using the OpenFOAM computational fluid dynamics package is proposed. After a preliminary validation and calibration of the OpenFOAM native Schnerr–Sauer interphase mass transfer model for cavitating flow, based on the experimental results on a 2D NACA66Mod hydrofoil, open water propeller performance and cavitation predictions are carried out. The OpenFOAM results are finally compared both with the available experimental measurements and with calculations carried out with StarCCM+ and with a proprietary boundary element method code, in order to assess the accuracy and the overall capabilities of the open-source tools (from meshing to post-processing) available in the OpenFOAM package. The comparison, in addition to assessing the accuracy of the open-source approach, is aimed to verify its advantages and drawbacks with respect to widely used solvers and to further verify the reliability of traditional boundary element method approaches that are still widely adopted for design and optimization (thanks to their extremely higher computational efficiency) in a very demanding test case.

scholarly journals Boundary Element Method Applied to Added Mass Coefficient Calculation of the Skewed Marine Propellers

2016 ◽  
Vol 23 (2) ◽  
pp. 25-31 ◽  
Author(s):  
Ehsan Yari ◽  
Hassan Ghassemi
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Rotational Velocity ◽  
Three Dimensional ◽  
Added Mass ◽  
Data Sets ◽  
Marine Propellers ◽  
Mass Coefficient ◽  
Dimensional Boundary ◽  
Element Method

AbstractThe paper mainly aims to study computation of added mass coefficients for marine propellers. A three-dimensional boundary element method (BEM) is developed to predict the propeller added mass and moment of inertia coefficients. Actually, only few experimental data sets are available as the validation reference. Here the method is validated with experimental measurements of the B-series marine propeller. The behavior of the added mass coefficients predicted based on variation of geometric and flow parameters of the propeller is calculated and analyzed. BEM is more accurate in obtaining added mass coefficients than other fast numerical methods. All added mass coefficients are nondimensionalized by fluid density, propeller diameter, and rotational velocity. The obtained results reveal that the diameter, expanded area ratio, and thickness have dominant influence on the increase of the added mass coefficients.

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

2001 ◽  
Vol 123 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Yin L. Young ◽  
Spyros A. Kinnas
Keyword(s):  
Numerical Analysis ◽  
Boundary Element Method ◽  
Numerical Method ◽  
Boundary Element ◽  
Present Method ◽  
Sheet Cavitation ◽  
Marine Vehicles ◽  
The Face ◽  
Element Method

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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