Numerical study of unsteady cavitating flows with RANS and DES models

Tian, Chunlai; Chen, Tairan; Zou, Tian

doi:10.1142/s0217984919502282

Cited by 8 publications

(3 citation statements)

References 36 publications

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“…They found that both LES and DES perform well and have better agreement with the experimental results. The fact that DES predicts cavitating flow better than the URANS is also reported in several other works (Huang et al , 2012; Maasch et al , 2015; Tian et al , 2019; Usta and Korkut, 2018).…”

Section: Introductionsupporting

confidence: 77%

Prediction of unsteady, internal turbulent cavitating flow using dynamic cavitation model

Ullas

Chatterjee

Vengadesan

2022

HFF

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Purpose Understanding the interaction of turbulence and cavitation is an essential step towards better controlling the cavitation phenomenon. The purpose of this paper is to bring out the efficacy of different modelling approaches to predict turbulence and cavitation-induced phase changes. Design/methodology/approach This paper compares the dynamic cavitation (DCM) and Schnerr–Sauer models. Also, the effects of different modelling methods for turbulence, unsteady Reynolds-averaged Navier–Stokes (URANS) and detached eddy simulations (DES) are also brought out. Numerical predictions of internal flow through a venturi are compared with experimental results from the literature. Findings The improved predictive capability of cavitating structures by DCM is brought out clearly. The temporal variation of the cavity size and velocity illustrates the involvement of re-entrant jet in cavity shedding. From the vapour fraction contours and the attached cavity length, it is found that the formation of the re-entrant jet is stronger in DES results compared with that by URANS. Variation of pressure, velocity, void fraction and the mass transfer rate at cavity shedding and collapse regions are presented. Wavelet analysis is used to capture the shedding frequency and also the corresponding occurrence of features of cavity collapse. Originality/value Based on the performance, computational time and resource requirements, this paper shows that the combination of DES and DCM is the most suitable option for predicting turbulent-cavitating flows.

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Section: Introductionsupporting

confidence: 77%

Prediction of unsteady, internal turbulent cavitating flow using dynamic cavitation model

Ullas

Chatterjee

Vengadesan

2022

HFF

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“…Then, the LES errors can be obtained. In summary, based on the previous research [20,23,25,36] on LES V&V, the value of r between 1 and 2 is more appropriate. Too large a value of r will make the computation capacity insufficient, while a smaller ratio will make it difficult to distinguish the LES and iteration errors.…”

Section: Application Of Vandv Approach In Waterjet Pumpmentioning

confidence: 99%

Verification and Validation of Large Eddy Simulation for Tip Clearance Vortex Cavitating Flow in a Waterjet Pump

Han

Long

et al. 2021

Energies

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In this paper, large eddy simulation (LES) was adopted to simulate the cavitating flow in a waterjet pump with emphasis on the tip clearance flow. The numerical results agree well with the experimental observations, which indicates that the LES method can make good predictions of the unsteady cavitating flows around a rotor blade. The LES verification and validation (LES V&V) analysis was used to reveal the influence of cavitation on the flow structures. It can be found that the LES errors in cavitating region are larger than those in the non-cavitating area, which is mainly caused by more complicated cavitating and tip clearance flow structures. Further analysis of the interaction between the cavitating and vortex flow by the relative vorticity transport equation shows that the stretching, dilatation and baroclinic torque terms have major effects on the generation and transport of vortex structure. Meanwhile the Coriolis force term and viscosity term also exacerbate the vorticity transport in the cavitating region. In addition, the flow loss characteristics of this pump are also revealed by the entropy production theory. It is indicated that the tip clearance flow and trailing edge wake flow cause the viscous dissipation and turbulent dissipation, and the cavitation can further enhance the instability of the flow field in the tip clearance.

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“…By combining the momentum equations for the gas phase and the liquid phase, the momentum equation for the mixture can be created, which has the following form [27]:…”

Section: Momentum Equationmentioning

confidence: 99%

Numerical Investigation of Cavitating Jet Flow Field with Different Turbulence Models

Li,

Xu,

et al. 2023

Mathematics

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In numerous industries such as drilling, peening, cleaning, etc., a cavitating jet is adopted. However, it is challenging to simulate the cavitating flow field numerically with accuracy. The flow field of the organ pipe cavitation nozzle is simulated in this research using the RNG k−ε, DES, and LES turbulence models. The LES model can more accurately predict the periodic shedding of a cavitating cloud, which is basically consistent with the jet morphology captured with a high−speed camera. The flow pattern, cavitating cloud evolution and shedding period of a cavitating jet are analyzed. The findings demonstrate that the LES model produces a cavitating effect inside the nozzle that is superior to those produced by the RNG k−ε and DES models. The vortex rings in the diffusion section are simulated using the LES model, which accelerates cavitation. The cavitating clouds of the organ pipe nozzle show periodic evolutions, with stages of generation, development, shedding and collapse. The periodic shedding of the cavitating clouds exhibits a similar pattern in the vorticities simulated using the LES model, and the vorticities display the small-scale structures where the cavitating bubbles collapse. This study can provide a reference for the simulation of a cavitating jet and the analysis of the cavitating mechanism.

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Numerical study of unsteady cavitating flows with RANS and DES models

Cited by 8 publications

References 36 publications

Prediction of unsteady, internal turbulent cavitating flow using dynamic cavitation model

Prediction of unsteady, internal turbulent cavitating flow using dynamic cavitation model

Verification and Validation of Large Eddy Simulation for Tip Clearance Vortex Cavitating Flow in a Waterjet Pump

Numerical Investigation of Cavitating Jet Flow Field with Different Turbulence Models

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