scholarly journals Small scale structure of homogeneous turbulent shear flow

2004 ◽  
Vol 16 (8) ◽  
pp. 2864-2876 ◽  
Author(s):  
D. Livescu ◽  
C. K. Madnia
Keyword(s):  
Shear Flow ◽  
Scale Structure ◽  
Turbulent Shear ◽  
Small Scale ◽  
Turbulent Shear Flow ◽  
Small Scale Structure

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

On the interactions between large-scale structure and finegrained turbulence in a free shear flow II. The development of spatial interactions in the mean

1978 ◽  
Vol 359 (1699) ◽  
pp. 497-523 ◽  
Keyword(s):  
Shear Flow ◽  
Shear Layer ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Free Shear Layer ◽  
Mean Flow ◽  
The Mean

Organized structures in turbulent shear flow have been observed both in the laboratory and in the atmosphere and ocean. Recent work on modelling such structures in a temporally developing, horizontally homogeneous turbulent free shear layer (Liu & Merkine 19766) has been extended to the spatially developing mixing layer, there being no available rational transformation between the two nonlinear problems. We consider the kinetic energy development of the mean flow, large-scale structure and finegrained turbulence with a conditional average, supplementing the usual time average, to separate the non-random from the random part of the fluctuations. The integrated form of the energy equations and the accompanying shape assumptions are used to derive ‘ amplitude ’ equations for the mean flow, characterized by the shear layer thickness, the non-random and the random components of flow (which are characterized by their respective energy densities). The closure problem was overcome by the shape assumptions which entered into the interaction integrals: the instability-wavelike large-scale structure was taken to be two-dimensional and the local vertical distribution function was obtained by solving the Rayleigh equation for various local frequencies; the vertical shape of the mean stresses of the fine-grained turbulence was estimated by making use of experimental results; the vertical shapes of the wave-induced stresses were calculated locally from their corresponding equations.

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.

Open-loop control of compensation for optical propagation through a turbulent shear flow

1998 ◽  
Author(s):  
C. Truman ◽  
Lenore McMackin ◽  
Robert Pierson ◽  
Kenneth Bishop ◽  
Ellen Chen
Keyword(s):  
Shear Flow ◽  
Open Loop ◽  
Turbulent Shear ◽  
Turbulent Shear Flow ◽  
Open Loop Control ◽  
Loop Control ◽  
Optical Propagation

scholarly journals Scale dependence of the alignment between strain rate and rotation in turbulent shear flow

2016 ◽  
Vol 1 (6) ◽  
Author(s):  
D. Fiscaletti ◽  
G. E. Elsinga ◽  
A. Attili ◽  
F. Bisetti ◽  
O. R. H. Buxton
Keyword(s):  
Shear Flow ◽  
Strain Rate ◽  
Scale Dependence ◽  
Turbulent Shear ◽  
Turbulent Shear Flow
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