Solid/free-surface juncture boundary layer and wake

Longo, Joseph; Huang, Hung-Pin; Stern, Frederick

doi:10.1007/s003480050232

Cited by 24 publications

(27 citation statements)

References 17 publications

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“…In the present study, instead of the Reynolds-averaged Navier-Stokes equations, we adopt the Reynolds-averaged vorticity transport equations, following the lines of our previous study (Longo et al, 1998). But the vorticity generation terms due to the presence of air-water interface are ignored in the analysis for simplicity.…”

Section: Vorticity Transportmentioning

confidence: 98%

“…The lateral gradients of wuwu are small for most of the region except near the cylinder. Longo et al (1998) explained the physical mechanism for the mean streamwise vortices generated in solid-interface juncture flow using the vorticity transport equation, which can be derived by taking the curl of the time-averaged NavierStokes equation. For a steady flow of constant density, the equation can be written as…”

Section: Reynolds Stressesmentioning

confidence: 99%

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The effect of air–water interface on the vortex shedding from a vertical circular cylinder

Suh

Yang

Stern

2011

Journal of Fluids and Structures

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Section: Vorticity Transportmentioning

confidence: 98%

Section: Reynolds Stressesmentioning

confidence: 99%

The effect of air–water interface on the vortex shedding from a vertical circular cylinder

Suh

Yang

Stern

2011

Journal of Fluids and Structures

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“…In these simulations, in which the inner secondary flow was resolved, the TKE increased near the rigid-lid boundary and a redistribution of energy from the surface normal components to the other two was also observed in this region. There is some controversy on this issue, since Longo et al (1998) and Sreedhar & Stern (1998) predict an increase of mean-square streamwise velocity fluctuations as the distance from the free surface decreases, while Grega et al (1995), in their experiments, measure an increase in this quantity. Similar discrepancies are found in the behaviour of the anisotropy-tensor profiles.…”

Section: Introductionmentioning

confidence: 98%

“…The existence of mean secondary flows in the corner (similar to those that occur in the closed ducts) adds complexity to the problem. Studies of turbulent flows in the corner formed by a vertical solid wall and a free surface have been performed, among others, by Grega et al (1995), Longo, Huang & Stern (1998), Sreedhar & Stern (1998), Hsu et al (2000) and Grega, Hsu & Wei (2002). Grega et al (1995) carried out numerical simulations in conjuction with experimental flow visualization and single-component laser-Doppler anemometry (LDA) velocity measurements.…”

Section: Introductionmentioning

confidence: 99%

Large-eddy simulations of ducts with a free surface

2003

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This work studies the momentum and energy transport mechanisms in the corner between a free surface and a solid wall. We perform large-eddy simulations of the incompressible fully developed turbulent flow in a square duct bounded above by a free-slip wall, for Reynolds numbers based on the mean friction velocity and the duct width equal to 360, 600 and 1000. The flow in the corner is strongly affected by the advection due to two counter-rotating secondary-flow regions present immediately below the free surface. Because of the convection of the inner eddy, as the free surface is approached, the friction velocity on the sidewall first decreases, then increases again. A similar behaviour is observed for the surface-parallel Reynolds-stress components, which first decrease and then increase again very close to the surface. The budgets of the Reynolds stresses show a strong reduction of all terms of the dissipation tensor in both the inner and outer near-corner regions. They exhibit a reduction in both production and dissipation towards the free surface. Very close to the solid boundary, within 15-20 viscous lengths of the sidewall, the turbulent kinetic energy production and the surface-parallel fluctuations rebound in the thin layer adjacent to the free surface. The Reynolds-stress anisotropy appears to be the main factor in the generation of the mean secondary flow. The multi-layer structure of the boundary layer near the free surface is also discussed.

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“…The vertical plate pierces the free surface in the channel and the resulting flow that develops locally near the two surfaces is dominated by both the presence of the bubbles and the boundary conditions. The single phase flow that exists at the juncture between a solid boundary and a free surface has been experimentally and numerically studied by Stern and collaborators, Sreedhar & Stern (1998) Longo et al (1998). The Reynolds averaged statistics revealed two counter-rotating streamwise vortical structure of relatively weak intensity.…”

Section: Introductionmentioning

confidence: 99%

Effect of Gravity on Sheared Turbulence Laden With Bubbles or Droplets

Lasheras¹

2004

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The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions. searching existing date sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate 10704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OM8 control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. REPORT DATE (DD-MM-YYYY)2. REPORT TYPE 13. DATES COVERED (From -To) This report studies the dynamics of particle-laden turbulent flows. Specifically, it addresses the effect of the turbulence on the concentration field and drift velocity of spherical particles. The coupling between the particle accumulation and the modification of the drift velocity of spherical particles. The coupling between the particle accumulation and the modification of the drift velocity is also investigated. Turbulent flows with and without mean shear are analyzed and the effect of the turbulent length scales on the behavior of the particles is described. The effect of the density ratio between the disperse and the continuous phase was considered in the two extreme cases of water droplets in air (1000) and air bubbles in water (1/1000). SUBJECT TERMSShared turbulence laden with bubbles or droplets. Dynamics of particle-laden turbulent flows. SECURITY CLASSIFICATION OF:17 Chapter 1

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Solid/free-surface juncture boundary layer and wake

Cited by 24 publications

References 17 publications

The effect of air–water interface on the vortex shedding from a vertical circular cylinder

The effect of air–water interface on the vortex shedding from a vertical circular cylinder

Large-eddy simulations of ducts with a free surface

Effect of Gravity on Sheared Turbulence Laden With Bubbles or Droplets

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