Large-eddy simulation of cavitation inception in a shear flow

Brandao, Filipe; Mahesh, Krishnan

doi:10.1016/j.ijmultiphaseflow.2021.103865

Cited by 11 publications

(3 citation statements)

References 35 publications

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“…All the PDFs are nearly symmetric, with the tails being more intense than Gaussian distributions with same mean and standard deviation (also shown). These trends are consistent with previously published data on pressure fluctuations in turbulent shear flows (Brandao & Mahesh 2022). In contrast, for isotropic turbulence, the PDFs are non-symmetric with longer negative tails, which increase with Reynolds number (Bappy et al.…”

Section: Resultssupporting

confidence: 93%

“…This is not always the case for turbulent shear layers. Wall pressure fluctuation measurements by Lee & Sung (2001) behind a backward-facing step exhibit a nearly Gaussian behaviour, in agreement with recent results of large eddy simulations by Brandao & Mahesh (2022), at least for non-cavitating flows. However, negative tails appear once cavitation starts.…”

Section: Introductionsupporting

confidence: 89%

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On the pressure field, nuclei dynamics and their relation to cavitation inception in a turbulent shear layer

Agarwal

Ram

et al. 2023

J. Fluid Mech.

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Cavitation inception in the turbulent shear layer developing behind a backward-facing step occurs at multiple points along quasi-streamwise vortices (QSVs), at a rate that increases with the Reynolds number (Re). This study investigates the evolution of the unsteady pressure field and the distribution of nuclei within and around the QSVs. The time-resolved volumetric velocity in the non-cavitating flow is measured using tomographic particle tracking, and the pressure is determined by spatial integration of the material acceleration. Analysis in Eulerian and Lagrangian reference frames reveals that the pressure is lower, and its minima last longer within the QSVs compared with the surrounding flow. The intermittent low pressure regions, whose sizes and shapes are consistent with those of the cavities, are likely to be preceded by axial vortex stretching and followed by contraction. Such phenomena have been observed before in simulations of stretched vortex elements. For the same axial straining, the pressure minima last longer with increasing Re, a trend elucidated in terms of viscous diffusion of the stretched vortex core. The impact of nuclei availability is studied under ‘natural’ and controlled seeding. Owing to differences in the saturation level of non-condensable gas, the microbubble concentration in the shear layer decreases with increasing Re, in contrast to the rate of cavitation events. Minor differences in entrainment rate into the shear layer also do not explain the substantial Re effects on cavitation inception. Hence, the Re scaling of inception appears to be dominated by trends of the pressure field.

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Section: Resultssupporting

confidence: 93%

Section: Introductionsupporting

confidence: 89%

On the pressure field, nuclei dynamics and their relation to cavitation inception in a turbulent shear layer

Agarwal

Ram

et al. 2023

J. Fluid Mech.

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“…Thus, the supercavitating underwater projectiles Brandao However, in the actual marine environment, the seawater flow is subjected to the shear stress, and the flow velocity presents the shear profile along the distance from the wall surface under the effects of confined walls such as coastal and target surfaces. [8][9][10][11][12] Research on the effects of shear flow has gained wide attention in recent years. By large-eddy simulation, et al examined the cavitation in the shear layer of a backward-facing step, and the simulation results were in good agreement with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Cavitation and Hydrodynamic Characteristics of Supercavitating Projectiles in the Shear Flow

Yuan

Zhao

Zhou

et al. 2023

J. Phys.: Conf. Ser.

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To investigate the cavitation and hydrodynamic characteristics of supercavitating projectiles in the shear flow, the Mixture multiphase and Schnerr-Sauer cavitation models are employed to simulate the underwater projectiles. The inflow average velocity is 600 m/s, and the shear rates range from 0 to 7500 s−1. In the uniform flow, the supercavity enveloping projectiles is vertically symmetrical. The drag is dominated by pressure drag, and the lift coefficient is 0. However, the supercavity is asymmetric in the shear flow, which deviates towards the low-speed side of projectiles. This is because the flow around projectiles runs faster on the high-speed side, and the vortices on the low-speed side entrain more fluid from the high-speed side. Thus, the projectiles suffer from normal shear stress orientating towards the low-speed side, and the lift coefficient turns negative. When the shear rate further increases, the projectile shoulder contacts water on the high-speed side, and the viscosity around projectiles is enhanced, resulting in the significant augmentation of the drag coefficient. As the water pressure is strongly larger than saturated vapor pressure on the low-speed side, the normal component of pressure acts more intensely towards the low-speed side of projectiles, and the lift coefficient is further decreased.

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Cavitation research with computational fluid dynamics: From Euler-Euler to Euler-Lagrange approach

Ji,

Wang,

Cheng

et al. 2024

J Hydrodyn

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Large-eddy simulation of cavitation inception in a shear flow

Cited by 11 publications

References 35 publications

On the pressure field, nuclei dynamics and their relation to cavitation inception in a turbulent shear layer

On the pressure field, nuclei dynamics and their relation to cavitation inception in a turbulent shear layer

Numerical Simulation of Cavitation and Hydrodynamic Characteristics of Supercavitating Projectiles in the Shear Flow

Cavitation research with computational fluid dynamics: From Euler-Euler to Euler-Lagrange approach

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