Cavitation on Model- and Full-Scale Marine Propellers: Steady And Transient Viscous Flow Simulations At Different Reynolds Numbers

Viitanen, Ville; Siikonen, Timo; Sánchez-Caja, Antonio

doi:10.3390/jmse8020141

Cited by 24 publications

(20 citation statements)

References 18 publications

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“…Shin et al (2018) [17] studied an adaptive grid refinement based on Q-criterion and showed a remarkable improvement in the capturing of tip vortex cavitation. Viitanen et al (2020) [18] also exhibited the significant grid resolution dependency of tip vortex cavitation for an open water propeller. This section discusses the grid sensitivity of the present numerical approach.…”

Section: Resultsmentioning

confidence: 92%

Feasibility Study of Rans in Predicting Propeller Cavitation in Behind-Hull Conditions

Zhang

Lai

et al. 2020

Polish Maritime Research

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The propeller cavitation not only affects the propulsive efficiency of a ship but also can cause vibration and noise. Accurate predictions of propeller cavitation are crucial at the design stage. This paper investigates the feasibility of the Reynolds-averaged Navier–Stokes (RANS) method in predicting propeller cavitation in behind-hull conditions, focusing on four aspects: (i) grid sensitivity; (ii) the time step effect; (iii) the turbulence model effect; and (iv) ability to rank two slightly different propellers. The Schnerr-Sauer model is adopted as the cavitation model. A model test is conducted to validate the numerical results. Good agreement on the cavitation pattern is obtained between the model test and computational fluid dynamics. Two propellers are computed, which have similar geometry but slightly different pitch ratios. The results show that RANS is capable of correctly differentiating the cavitation patterns between the two propellers in terms of the occurrence of face cavitation and the extent of sheet cavitation; moreover, time step size is found to slightly affect sheet cavitation and has a significant impact on the survival of the tip vortex cavitation. It is also observed that grid refinement is crucial for capturing tip vortex cavitation and the two-equation turbulence models used – realizable k-ε and shear stress transport (SST) k-ω – yield similar cavitation results.

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Section: Resultsmentioning

confidence: 92%

Feasibility Study of Rans in Predicting Propeller Cavitation in Behind-Hull Conditions

Zhang

Lai

et al. 2020

Polish Maritime Research

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“…Recently we have investigated the Reynolds number sensitiveness of different cavitation types observed on a ship's propeller [31]. For the case of static hydrofoils exhibiting similar phenomena as shown here, this remains to be assessed.…”

Section: Discussionmentioning

confidence: 94%

“…Usually, the mass-transfer rate is proportional to a pressure difference from a saturated state or to a square root of that. In this study, we employ a mass-transfer model that is similar to that of Choi and Merkle [30], described in [24,31]. The empirical parameters of the cavitation model are calibrated by Sipilä [3].…”

Section: Mass and Energy Transfermentioning

confidence: 99%

Compressible Two-Phase Viscous Flow Investigations of Cavitation Dynamics for the ITTC Standard Cavitator

et al. 2020

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In this paper, the ITTC Standard Cavitator is numerically investigated in a cavitation tunnel. Simulations at different cavitation numbers are compared against experiments conducted in the cavitation tunnel of SVA Potsdam. The focus is placed on the numerical prediction of sheet-cavitation dynamics and the analysis of transient phenomena. A compressible two-phase flow model is used for the flow solution, and two turbulence closures are employed: a two-equation unsteady RANS model, and a hybrid RANS/LES model. A homogeneous mixture model is used for the two phases. Detailed analysis of the cavitation shedding mechanism confirms that the dynamics of the sheet cavitation are dictated by the re-entrant jet. The break-off cycle is relatively periodic in both investigated cases with approximately constant shedding frequency. The CFD predicted sheet-cavitation shedding frequencies can be observed also in the acoustic measurements. The Strouhal numbers lie within the usual ranges reported in the literature for sheet-cavitation shedding. We furthermore demonstrate that the vortical flow structures can in certain cases develop striking cavitating toroidal vortices, as well as pressure wave fronts associated with a cavity cloud collapse event. To our knowledge, our numerical analyses are the first reported for the ITTC standard cavitator.

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“…Even though the calibration was effective for two dimensional case, when employed for three-dimensional propeller analysis, the model overpredicted sheet cavitation and struggled with a cavitation rope vortex. Recently, a study by Viitanen et al [11] confirmed the observations noted in [8]; despite different models, cavitation rope prediction is heavily influenced by grid refinements which minimize dissipation and thus conserve the rope. Zwart and Kunz models, unlike Schnerr-Sauer, utilize empirical constants; hence, their accuracy and applicability heavily depend on the values employed for a case in question.…”

Section: Introductionmentioning

confidence: 80%

Cavitation Model Calibration Using Machine Learning Assisted Workflow

et al. 2020

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Conventional cavitation assessment methodology in industrial and scientific applications generally depends on cavitation models utilizing homogeneous mixture assumption. These models have been extensively assessed, modified and expanded to account for deficiencies of their predecessors. Unfortunately, none of the proposed models can be classified as the universal solution for all engineering applications, with usage mainly directed by experience or general availability of the models. In this study we propose a workflow through which the empirical constants governing the phase change of the Kunz mixture cavitation model can be calibrated for a given application or a series of problems, with machine learning as a tool for parameter estimation. The proposed approach was validated on a three-dimensional propeller test case with results in excellent agreement for the case in question. Results for thrust and torque were within 2% with cavity extents differing by up to 20%. This is a significant improvement when compared to previously proposed parameters. Despite the lack of generalization due to the limited nature of the dataset on which the model was trained, the proposed parameters entail acceptable results for similar cases as well. The overall methodology is applicable to other problems as well and should lead to more accurate cavitation predictions.

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Cavitation on Model- and Full-Scale Marine Propellers: Steady And Transient Viscous Flow Simulations At Different Reynolds Numbers

Cited by 24 publications

References 18 publications

Feasibility Study of Rans in Predicting Propeller Cavitation in Behind-Hull Conditions

Feasibility Study of Rans in Predicting Propeller Cavitation in Behind-Hull Conditions

Compressible Two-Phase Viscous Flow Investigations of Cavitation Dynamics for the ITTC Standard Cavitator

Cavitation Model Calibration Using Machine Learning Assisted Workflow

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