The anisotropy of the small scale structure in high Reynolds number (R[sub λ]∼1000) turbulent shear flow

2000 ◽  
Vol 12 (11) ◽  
pp. 2976 ◽  
Author(s):  
X. Shen ◽  
Z. Warhaft
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
High Reynolds Number ◽  
Scale Structure ◽  
Turbulent Shear ◽  
Small Scale ◽  
Turbulent Shear Flow ◽  
Small Scale Structure ◽  
High Reynolds

A Generalized Taylor Hypothesis With Application for High Reynolds Number Turbulent Shear Flows

1965 ◽  
Vol 32 (4) ◽  
pp. 735-739 ◽  
Author(s):  
Gunnar Heskestad
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Time Derivative ◽  
Turbulent Shear ◽  
Mean Square ◽  
Turbulent Shear Flow ◽  
Taylor Hypothesis ◽  
High Turbulence ◽  
The Mean ◽  
High Reynolds

An approximate relation between the partial time and space derivatives of the velocity in a high Reynolds number turbulent shear flow (where high turbulence intensities prevail) is obtained. The relation is used to compute the mean-square space derirative from the mean-square time derivative, the latter being more accessible by hot-wire techniques.

Effect of the shear parameter on velocity-gradient statistics in homogeneous turbulent shear flow

2011 ◽  
Vol 678 ◽  
pp. 14-40 ◽  
Author(s):  
JUAN C. ISAZA ◽  
LANCE R. COLLINS
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Scaling Laws ◽  
Stokes Equations ◽  
Strain Tensor ◽  
Turbulent Shear ◽  
Small Scale ◽  
Turbulent Shear Flow ◽  
Velocity Statistics ◽  
Shear Parameter

The effect of the shear parameter on the small-scale velocity statistics in an homogeneous turbulent shear flow is investigated using direct numerical simulations (DNSs) of the incompressible Navier–Stokes equations on a 5123 grid. We use a novel pseudo-spectral algorithm that allows us to set the initial value of the shear parameter in the range 3–30 without the shortcomings of previous numerical approaches. We find that the tails of the probability distribution function of components of the vorticity vector and rate-of-strain tensor are progressively distorted with increasing shear parameter. Furthermore, we show that the shear parameter has a direct effect on the structure of the vorticity field, which manifests through changes in its alignment with the eigenvectors of the rate-of-strain tensor. We also find that increasing the shear parameter causes the main contribution to enstrophy production to shift from the nonlinear terms to the rapid terms (terms that are proportional to the mean shear) due to the aforementioned changes in the alignment. We attempt to explain these trends using viscous rapid distortion theory; however, while the theory does capture some effects of the shear parameter, it fails to predict the correct dependence on Reynolds number. Comparisons with recent experiments are also shown. The trends predicted by the DNS and the experiments are in good agreement. Moreover, the prefactors in the Reynolds number scaling laws for the skewness and flatness of the longitudinal velocity derivative are shown to have a statistically significant dependence on the shear parameter.

scholarly journals When is high Reynolds number shear flow not turbulent?

2017 ◽  
Vol 824 ◽  
pp. 1-4 ◽  
Author(s):  
Steven A. Balbus
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
High Reynolds Number ◽  
Laboratory Experiments ◽  
Numerical Study ◽  
Accretion Discs ◽  
Large Reynolds Number ◽  
Rotating Flow ◽  
General Tendency ◽  
High Reynolds

Rotating flow in which the angular velocity decreases outward while the angular momentum increases is known as ‘quasi-Keplerian’. Despite the general tendency of shear flow to break down into turbulence, this type of flow seems to maintain stability at very large Reynolds number, even when nonlinearly perturbed, a behaviour that strongly influences our understanding of astrophysical accretion discs. Investigating these flows in the laboratory is difficult because secondary Ekman flows, caused by the retaining Couette cylinders, can become turbulent on their own. A recent high Reynolds number numerical study by Lopez & Avila (J. Fluid Mech., vol. 817, 2017, pp. 21–34) reconciles apparently discrepant laboratory experiments by confirming that this secondary flow recedes toward the axial boundaries of the container as the Reynolds number is increased, a result that enhances our understanding of nonlinear quasi-Keplerian flow stability.

On the small scale structure of simple shear flow

1998 ◽  
Vol 10 (3) ◽  
pp. 662-673 ◽  
Author(s):  
Sandeep Garg ◽  
Z. Warhaft
Keyword(s):  
Shear Flow ◽  
Simple Shear ◽  
Scale Structure ◽  
Small Scale ◽  
Simple Shear Flow ◽  
Small Scale Structure
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