Prediction of Unsteady Developed Tip Vortex Cavitation and Its Effect on the Induced Hull Pressures

Kim, Seungnam; Kinnas, Spyros A.

doi:10.3390/jmse8020114

Cited by 12 publications

(3 citation statements)

References 14 publications

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“…Du and Kinnas [16] developed a 3-D flow separation model for open propellers with a blunt trailing edge. Kim and Kinnas [17] focused on predicting unsteady developed tip vortex cavitation and its effect on induced hull pressures and the unsteady performance of ducted propellers in a ship behind condition [18]. Additionally, the boundary layer strip theory allows for the inclusion of the effects of viscosity [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

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

You,

Kinnas

2023

JMSE

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This research addresses the demand for a computationally efficient numerical tool capable of predicting 3-D turbulent flows over 3-D hydrofoils, a critical step in ultimately addressing marine propeller or turbine performance. The related software development and its applications are conducted by employing the vorticity-based approach known as the viscous vorticity equation (VISVE). In particular, an existing 3-D laminar VISVE solver was modified in order to handle 3-D turbulent flow scenarios. The extension incorporates the k−ω SST model into the 3-D VISVE solver by using the finite volume method (FVM), thereby broadening its application to turbulent flows. The model was then tested in the case of turbulent flows over 3-D hydrofoils. The results were found to not be sensitive to either grid or time step size and to be in very good agreement with those obtained using a Reynolds-averaged Navier–Stokes (RANS) solver. This solver offers distinct advantages, including a significantly reduced computational domain size and reduced computational costs through its vorticity-based approach. Notably, turbulence concentration within boundary layers and free shear flows does not compromise the method’s computational efficiency. The simplified meshing process, which automatically generates the grids based on the number of panels on the hydrofoil, enhances accessibility for researchers and engineers.

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Section: Introductionmentioning

confidence: 99%

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

You,

Kinnas

2023

JMSE

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“…Hydrodynamic noise is one of three major noises of underwater vehicles, and studying and controlling it are important [1][2][3][4][5][6][7][8][9][10]. The hydrodynamic noise is mainly caused by the velocity and pressure fluctuation in turbulent flow.…”

Section: Introduction and Principle Headingsmentioning

confidence: 99%

Noise Reduction Effect of Superhydrophobic Surfaces with Streamwise Strip of Channel Flow

et al. 2021

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Superhydrophobic surface is a promising technology, but the effect of superhydrophobic surface on flow noise is still unclear. Therefore, we used alternating free-slip and no-slip boundary conditions to study the flow noise of superhydrophobic channel flows with streamwise strips. The numerical calculations of the flow and the sound field have been carried out by the methods of large eddy simulation (LES) and Lighthill analogy, respectively. Under a constant pressure gradient (CPG) condition, the average Reynolds number and the friction Reynolds number are approximately set to 4200 and 180, respectively. The influence on noise of different gas fractions (GF) and strip number in a spanwise period on channel flow have been studied. Our results show that the superhydrophobic surface has noise reduction effect in some cases. Under CPG conditions, the increase in GF increases the bulk velocity and weakens the noise reduction effect. Otherwise, the increase in strip number enhances the lateral energy exchange of the superhydrophobic surface, and results in more transverse vortices and attenuates the noise reduction effect. In our results, the best noise reduction effect is obtained as 10.7 dB under the scenario of the strip number is 4 and GF is 0.5. The best drag reduction effect is 32%, and the result is obtained under the scenario of GF is 0.8 and strip number is 1. In summary, the choice of GF and the number of strips is comprehensively considered to guarantee the performance of drag reduction and noise reduction in this work.

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“…In terms of mathematical modeling, lifting-surface sheet cavitation can be predicted up to a desirable degree of accuracy using ideal flow-based numerical methods; see the work of [18,19] for partially and [20] for supercavitating regimes. Potential-based methods have been widely used in the prediction of fluctuating pressures on ship hulls induced by marine propellers (see the work of [21]) operating in regimes of partial as well as tip-vortex cavitation. The main intricacy in predicting the flow around a cavitating lifting surface using non-linear cavity theory, or namely treating the free-streamline problem, lies in the fact that the extent, as well as the shape of the cavity, are unknowns determined as a part of the solution.…”

Section: Introductionmentioning

confidence: 99%

An Adjoint Optimization Prediction Method for Partially Cavitating Hydrofoils

Anevlavi

Belibassakis

2021

JMSE

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Much work has been done over the past years to obtain a better understanding, predict and alleviate the effects of cavitation on the performance of lifting surfaces for hydrokinetic turbines and marine propellers. Lifting-surface sheet cavitation, when addressed as a free-streamline problem, can be predicted up to a desirable degree of accuracy using numerical methods under the assumptions of ideal flow. Typically, a potential solver is used in conjunction with geometric criteria to determine the cavity shape, while an iterative scheme ensures that all boundary conditions are satisfied. In this work, we propose a new prediction model for the case of partially cavitating hydrofoils in a steady flow that treats the free-streamline problem as an inverse problem. The objective function is based on the assumption that on the cavity boundary, the pressure remains constant and is evaluated at each optimization cycle using a source-vorticity BEM solver. The attached cavity is parametrized using B-splines, and the control points are included in the design variables along with the cavitation number. The sensitivities required for the gradient-based optimization are derived using the continuous adjoint method. The proposed numerical scheme is compared against other methods for the NACA 16-series hydrofoils and is found to predict well both the cavity shape and cavitation number for a given cavity length.

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Prediction of Unsteady Developed Tip Vortex Cavitation and Its Effect on the Induced Hull Pressures

Cited by 12 publications

References 14 publications

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

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

Noise Reduction Effect of Superhydrophobic Surfaces with Streamwise Strip of Channel Flow

An Adjoint Optimization Prediction Method for Partially Cavitating Hydrofoils

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