Propeller tip-vortex cavitation and its broadband noise

Bosschers, Johan

doi:10.3990/1.9789492679529

Cited by 15 publications

(27 citation statements)

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“…The next example is a cavitating tip vortex originating from an elliptical planform wing with a root chord length of 0.1256 m [51,52]. This is a typical case for simulating cavitating tip vortices, which are commonly found on ship propellers.…”

Section: Isolated Cavitating Vortexmentioning

confidence: 99%

And…Action! Setting the Scene for Accurate Visual CFD Comparisons Using Ray Tracing

Klapwijk

Lemaire

2021

JMSE

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Increased graphical capabilities of contemporary computer hardware make ray tracing possible for a much wider range of applications. In science, and numerical fluid mechanics in particular, visual inspections still play a key role in both understanding flows, predicted by computational fluid dynamics, exhibiting features observable in real-life, such as interfaces or smoke, and when comparing such flows against experimental observations. Usually, little attention is paid to the visualisation itself, unless when the render is used solely for its eye-catching appearance. In this work, we argue that the use of ray tracing software can help make comparisons between computational and experimental fluid dynamics more robust and meaningful, and that, in some cases, it is even a necessity. Several visualisation problems which can be overcome through application of this methodology are discussed, and the use of ray tracing is exemplified for several common test cases in the maritime field. Using these examples the benefits of ray tracing are shown, and it is concluded that ray tracing can improve the reliability of scientific visual comparisons.

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Section: Isolated Cavitating Vortexmentioning

confidence: 99%

And…Action! Setting the Scene for Accurate Visual CFD Comparisons Using Ray Tracing

Klapwijk

Lemaire

2021

JMSE

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“…The type, extension and dynamics of the propeller cavitation are dependent on the propeller geometry, its operating condition, water quality as well as the wake flow of the ship's hull in front of the propeller. Amongst the different propeller cavitation types, such as bubble, sheet, cloud, and vortex, the ship propellers commonly operate in conditions where the sheet and tip vortex cavitation are observed in combination (Bosschers 2018).…”

Section: Introductionmentioning

confidence: 99%

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

Sezen

Atlar

2021

Ship Technology Research

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This study focuses on the investigation of cavitating flow around the benchmark INSEAN E779A model propeller with the main aim of further improving the computational efficiency of the tip vortex cavitation (TVC) modelling by using a commercial CFD solver. Also, the effects of various key computational parameters including, numerical modelling, grid size, timestep, water quality and boundary layer resolution, on the TVC formation and its extension in the propeller slipstream are investigated systematically.The numerical simulations are conducted in uniform and open water conditions using RANS, DES and LES solvers implemented in the commercial CFD code, Start CCM+. In order to achieve the aim of the study, an alternative and new Vorticity-based Adaptive Mesh Refinement (V-AMR) technique is introduced for enhanced modelling of the TVC on the blades and downstream. For the CFD modelling of cavitation, the Schneer Sauer cavitation model based on the reduced Rayleigh Plesset equation is used for the sheet, tip and hub vortex cavitation. The hydrodynamic results and cavity patterns are validated with the experimental data. The results show that the application of the V-AMR technique further improves the representation of the TVC with minimal increase in computational cost. However, the eddy viscosity at the propeller blade tips increases with applying the V-AMR technique using the RANS solver due to its inherent modelling errors for the solution of the flow inside the tip vortex. This consequently results in an insufficient extension of TVC in the propeller slipstream compared to the predictions by the DES and LES based numerical solvers. Also, the evolution of the TVC is found to be sensitive to the boundary layer resolution when the standard RANS solver is used. The study will help to widen further applications of the CFD methods involving TVC, particularly for propeller induced underwater noise prediction and analysis.

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“…Therefore, there is a large difference between the SPL of a propeller operating in non-cavitating and cavitating conditions. As a result, the most important factor controlling the URN of a propeller is the cavity inception speed (CIS) [6].…”

Section: Introductionmentioning

confidence: 99%

Investigations of tip vortex mitigation by using roughness

et al. 2020

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The application of artificial roughness to mitigate tip vortex cavitation inception is analyzed through numerical and experimental investigations carried out on an elliptical foil. Different roughness configurations and sizes are tested and effects on cavitation inception, drag, and lift, are studied. Implicit Large Eddy Simulation (ILES) is employed to conduct the simulation on a proper grid resolution having the tip vortex spatial resolution as fine as 0.062 mm. Two different approaches including using a rough wall function and resolving the flow around roughness elements are evaluated. New experiments, performed in the cavitation tunnel at Kongsberg Hydrodynamic Research Centre, for the rough foil are presented.The vortical structures and vorticity magnitude distributions are employed to demonstrate how different roughness patterns and configurations contribute to the vortex roll-up and consequently on the tip vortex strength.It is found that the application of roughness on the leading edge, tip region and trailing edge of the suction side are acceptable to mitigate the tip vortex and also to limit the performance degradation. This is regarded to be in close relation with the way that the tip vortex forms in the studied operating condition. The analysis of boundary layer characteristics shows a separation line caused by roughness is the reason for a more even distribution of vorticity over the tip compared to the smooth foil condition leading to a reduction in vortex strength. For the optimum roughness pattern, both the numerical results and experimental measurements show a decrease in the tip vortex cavitation inception as large as 33 % compared to the smooth foil condition with a drag force increase observed to be less than 2 %.

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Propeller tip-vortex cavitation and its broadband noise

Cited by 15 publications

References 0 publications

And…Action! Setting the Scene for Accurate Visual CFD Comparisons Using Ray Tracing

And…Action! Setting the Scene for Accurate Visual CFD Comparisons Using Ray Tracing

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

Investigations of tip vortex mitigation by using roughness

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