The structure of highly sheared turbulence

Souza, F. A. de; Nguyen, Vinh; Tavoularis, Stavros

doi:10.1017/s0022112095004216

Cited by 34 publications

(32 citation statements)

References 5 publications

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“…Based on DNS and windtunnel experiments, found that the turbulence properties are most sensitive to S * , and that m 12 tends to decrease with increasing S * . De Souza et al (1995) investigated USF with high shear in a high-speed windtunnel and found a similar decrease in m 12 compared to 'low-shear' USF. A numerical investigation by Table 4.…”

Section: The Formation Of Horseshoe Vortices In Usfmentioning

confidence: 82%

“…The streamwise Taylor microscale λ 11 was estimated as (De Souza et al 1995) λ 11 12ν (2k) , (3.8) and the Kolmogorov microscale η was computed as…”

Section: Time-averaged Flow Measurementsmentioning

confidence: 99%

“…As shown in table 4, the time-averaged turbulence properties of the current USF are not very different from those in previous realizations with comparable values of Re λ11 and S * . Previous authors have investigated the effect of Re λ11 and S * on the turbulence properties and in particular on the shear stress anisotropy m 12 , which, in general, is the most sensitive indicator of the turbulence structure (De Souza et al 1995). Based on DNS and windtunnel experiments, found that the turbulence properties are most sensitive to S * , and that m 12 tends to decrease with increasing S * .…”

Section: The Formation Of Horseshoe Vortices In Usfmentioning

confidence: 99%

“…Tavoularis & Corrsin 1981;Rohr et al 1988;De Souza, Nguyen & Tavoularis 1995;Ferchichi & Tavoularis 2000;Shen & Warhaft 2000;Isaza, Warhaft & Collins 2009). These studies reported measurements of the Reynolds stresses and other statistical properties of turbulence and discussed the evolution of the turbulence kinetic energy, the turbulence anisotropy, and the fine structure under the influence of uniform shear.…”

Section: Introductionmentioning

confidence: 99%

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Coherent structures in uniformly sheared turbulent flow

Vanderwel

Tavoularis

2011

J. Fluid Mech.

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Uniformly sheared turbulent flow has been generated in a water tunnel and its instantaneous structure has been examined using flow visualization and particle image velocimetry. The shear-rate parameter was approximately equal to 13 and the streamwise turbulence Reynolds number was approximately 150. The flow was found to consist of regions with nearly uniform velocity, which were separated by regions of high shear containing large vortices. The concentration of vortices and the distributions of their directions of rotation, strengths, sizes and shapes have been determined. These results demonstrate that horseshoe/hairpin-shaped vortices were prevalent, even though wall effects were negligible in this flow. Both 'upright' and 'inverted' vortices have been observed, in contrast to turbulent boundary layers, in which only 'upright' vortices can be found, suggesting that the presence of the wall may suppress the development of 'inverted' structures. Our observations demonstrate that the dominant coherent structures of fully developed USF are very different from the structures observed in the flow exiting the shear-generating apparatus, which points to an insensitivity of the former to initial effects.

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Section: The Formation Of Horseshoe Vortices In Usfmentioning

confidence: 82%

“…The streamwise Taylor microscale λ 11 was estimated as (De Souza et al 1995) λ 11 12ν (2k) , (3.8) and the Kolmogorov microscale η was computed as…”

Section: Time-averaged Flow Measurementsmentioning

confidence: 99%

Section: The Formation Of Horseshoe Vortices In Usfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Coherent structures in uniformly sheared turbulent flow

Vanderwel

Tavoularis

2011

J. Fluid Mech.

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“…The data from Webster [1964] and Piccirillo and van Atta [1997] are excluded due to low Reynolds numbers. High initial shear number cases [Lee et al, 1990;de Souza et al, 1995;Jacobitz et al, 1997;Jacobitz and Sarkar, 1999] are also excluded because it is not clear whether these flows eventually reach a self-similar state or not.…”

Section: Discussionmentioning

confidence: 99%

Parameterizing individual effects of shear and stratification on mixing in stably stratified shear flows

Shimizu

2012

J. Geophys. Res.

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[1] This study proposes new parameterizations of diapycnal mixing by reanalyzing the results of previous laboratory and numerical experiments on homogeneous stably stratified shear flows. Unlike previous studies that use either the turbulent Froude number Fr or gradient Richardson number Ri g , this study parameterizes nondimensional momentum and buoyancy fluxes as functions of Fr and a turbulent shear number Sh, in order to quantify individual effects of shear and stratification. Turbulent momentum flux is found to depend linearly on Sh and to decrease monotonically with decreasing Fr. Turbulent buoyancy flux has a peak at moderate Fr. With increasing Sh, it decreases and increases at high and low Fr, respectively. The increase of Sh also cause relatively small but significant decreases of nondimensional turbulent properties, such as the nondimensional conversion rate of turbulent potential energy to background potential energy. The proposed parameterizations lie within the scatter of limited available field data. The parameterizations may be reduced to Ri g -based ones by incorporating the relationship between Ri g and turbulence intensity observed in the field. Existing stability functions for two-equation turbulent closure schemes are found to over-predict mixing efficiency at low Fr.

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Large eddy simulation of homogeneous shear flows with several subgrid-scale models

Wang

Jacobitz

Rutland

2006

Int. J. Numer. Meth. Fluids

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SUMMARYIn this article, large eddy simulation is used to simulate homogeneous shear ows. The spatial discretization is accomplished by the spectral collocation method and a third-order Runge-Kutta method is used to integrate the time-dependent terms. For the estimation of the subgrid-scale stress tensor, the Smagorinsky model, the dynamic model, the scale-similarity model and the mixed model are used. Their predicting performance for homogeneous shear ow is compared accordingly. The initial Reynolds number varies from 33 to 99 and the initial shear number is 2. Evolution of the turbulent kinetic energy, the growth rate, the anisotropy component and the subgrid-scale dissipation rate is presented. In addition, the performance of several ÿlters is examined.

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The structure of highly sheared turbulence

Cited by 34 publications

References 5 publications

Coherent structures in uniformly sheared turbulent flow

Coherent structures in uniformly sheared turbulent flow

Parameterizing individual effects of shear and stratification on mixing in stably stratified shear flows

Large eddy simulation of homogeneous shear flows with several subgrid-scale models

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