Beam propagation and wavefront-phase integrals in high Reynolds number shear layers and jets

1998 ◽  
Author(s):  
P. Dimotakis ◽  
H. Catrakis ◽  
D. Fourguette
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Beam Propagation ◽  
Shear Layers ◽  
High Reynolds

scholarly journals Flow structure and optical beam propagation in high-Reynolds-number gas-phase shear layers and jets

2001 ◽  
Vol 433 ◽  
pp. 105-134 ◽  
Author(s):  
P. E. DIMOTAKIS ◽  
H. J. CATRAKIS ◽  
D. C. FOURGUETTE
Keyword(s):  
Reynolds Number ◽  
Gas Phase ◽  
High Reynolds Number ◽  
Beam Propagation ◽  
Shear Layers ◽  
Optical Beam ◽  
Index Of Refraction ◽  
Phase Behaviour ◽  
Turbulent Region ◽  
High Reynolds

We report on the structure of the scalar index-of-refraction field generated by turbulent, gas-phase, incompressible and compressible shear layers and incompressible jets, and on associated beam-propagation aero-optical phenomena. Using simultaneous imaging of the optical-beam distortion and the turbulent-flow index-of-refraction field, wavefront-phase functions were computed for optical beams emerging from the turbulent region in these free-shear flows, in an aero-optical regime producing weak wavefront distortions. Spatial wavefront-phase behaviour is found to be dominated by the large-scale structure of these flows. A simple level-set representation of the index-of-refraction field in high-Reynolds-number, incompressible shear layers is found to provide a good representation of observed wavefront-phase behaviour, indicating that the structure of the unsteady outer boundaries of the turbulent region provides the dominant contributions.

Thin Shear Layers in High Reynolds Number Turbulence—DNS Results

2013 ◽  
Vol 91 (4) ◽  
pp. 895-929 ◽  
Author(s):  
Takashi Ishihara ◽  
Yukio Kaneda ◽  
Julian C. R. Hunt
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Shear Layers ◽  
High Reynolds

Large-scale refractive turbulent interfaces and aero-optical interactions in high Reynolds number compressible separated shear layers

2006 ◽  
Vol 7 ◽  
pp. N54 ◽  
Author(s):  
HARIS J. CATRAKIS ◽  
ROBERTO C. AGUIRRE ◽  
JENNIFER C. NATHMAN ◽  
PHILIP J. GARCIA
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Large Scale ◽  
Shear Layers ◽  
High Reynolds

scholarly journals A self-sustaining process theory for uniform momentum zones and internal shear layers in high Reynolds number shear flows

2020 ◽  
Vol 901 ◽  
Author(s):  
Brandon Montemuro ◽  
Christopher M. White ◽  
Joseph C. Klewicki ◽  
Gregory P. Chini
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Shear Flows ◽  
Shear Layers ◽  
Process Theory ◽  
High Reynolds ◽  
Image Position

Abstract

The mechanics of the formation region of vortices behind bluff bodies

1966 ◽  
Vol 25 (2) ◽  
pp. 401-413 ◽  
Author(s):  
J. H. Gerrard
Keyword(s):  
Reynolds Number ◽  
High Reynolds Number ◽  
Free Stream ◽  
Shear Layers ◽  
Bluff Bodies ◽  
Formation Region ◽  
Splitter Plates ◽  
Free Shear Layers ◽  
High Reynolds

The characteristic lengths of the oscillating wakes of bluff bodies is discussed; in particular, those used in the universal non-dimensional frequencies proposed by Roshko (1954b) and Goldburg, Washburn & Florsheim (1965). It is concluded that these are equivalent at high Reynolds number. A closer examination leads to the conclusion that there are two simultaneous characteristic lengths; the scale of the formation region, and the width to which the free shear layers diffuse. Discussion of the mechanics of the formation region results in a physical basis for the determination of the frequency by these two characteristic lengths. The ideas developed are applied to the effects of splitter plates in the wake. The possibility of a high-Reynolds-number symmetrical formation region is suggested as an explanation of the very small lift values observed in the absence of free-stream disturbances.

Energy constraints in forced recirculating MHD flows

1998 ◽  
Vol 375 ◽  
pp. 319-343 ◽  
Author(s):  
D. KINNEAR ◽  
P. A. DAVIDSON
Keyword(s):  
Reynolds Number ◽  
Kinetic Energy ◽  
High Reynolds Number ◽  
Body Force ◽  
Model Problem ◽  
Shear Layers ◽  
The Body ◽  
Strong Constraint ◽  
High Reynolds ◽  
Stream Transport

We are concerned here with forced steady recirculating flows which are laminar, two-dimensional and have a high Reynolds number. The body force is considered to be prescribed and independent of the flow, a situation which arises frequently in magnetohydrodynamics. Such flows are subject to a strong constraint. Specifically, the body force generates kinetic energy throughout the flow field, yet dissipation is confined to narrow singular regions such as boundary layers. If the flow is to achieve a steady state, then the kinetic energy which is continually generated within the bulk of the flow must find its way to the dissipative regions. Now the distribution of u2/2 is governed by a transport equation, in which the only cross-stream transport of energy is diffusion, v∇2 (u2/2). It follows that there are only two possible candidates for the transport of energy to the dissipative regions: the energy could be diffused to the shear layers, or else it could be convected to the shear layers through entrainment of the streamlines. We investigate both options and show that neither is a likely candidate at high Reynolds number. We then describe numerical experiments for a model problem designed to resolve these issues. We show that, at least for our model problem, no stable steady solution exists at high Reynolds number. Rather, as soon as the Reynolds number exceeds a modest value of around 10, the flow becomes unstable via a supercritical Hopf bifurcation.

scholarly journals Prograde vortices, internal shear layers and the Taylor microscale in high-Reynolds-number turbulent boundary layers

2021 ◽  
Vol 920 ◽  
Author(s):  
Michael Heisel ◽  
Charitha M. de Silva ◽  
Nicholas Hutchins ◽  
Ivan Marusic ◽  
Michele Guala
Keyword(s):  
Reynolds Number ◽  
Boundary Layers ◽  
High Reynolds Number ◽  
Shear Layers ◽  
Turbulent Boundary Layers ◽  
High Reynolds

Abstract

Sign in / Sign up

Export Citation Format

Share Document