Turbulent mixing in plane and axisymmetric shear layers

Predictions of turbulent mixing in axisymmetric compressible shear layers

AIAA Journal ◽

10.2514/3.11097 ◽

1992 ◽

Vol 30 (6) ◽

pp. 1529-1536 ◽

Cited By ~ 22

Author(s):

K. Viswanathan ◽

P. J. Morris

Keyword(s):

Turbulent Mixing ◽

Shear Layers

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Free Turbulent Shear Layers on Plug Nozzles

Journal of Fluids Engineering ◽

10.1115/1.3448749 ◽

1977 ◽

Vol 99 (2) ◽

pp. 301-308

Author(s):

C. J. Scott ◽

D. R. Rask

Keyword(s):

Turbulent Mixing ◽

Schmidt Number ◽

Error Function ◽

Mixing Layer ◽

Shear Layers ◽

Turbulent Shear ◽

Gas Chromatograph ◽

Plug Nozzle ◽

Turbulent Schmidt Number ◽

Plug Nozzles

Two-dimensional, free, turbulent mixing between a uniform stream and a cavity flow is investigated experimentally in a plug nozzle, a geometry that generates idealized mixing layer conditions. Upstream viscous layer effects are minimized through the use of a sharp-expansion plug nozzle. Experimental velocity profiles exhibit close agreement with both similarity analyses and with error function predictions. Refrigerant-12 was injected into the cavity and concentration profiles were obtained using a gas chromatograph. Spreading factors for momentum and mass were determined. Two methods are presented to determine the average turbulent Schmidt number. The relation Sct = Sc is suggested by the data for Sc < 2.0.

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The effect of initial conditions on the development of a free shear layer

Journal of Fluid Mechanics ◽

10.1017/s0022112066001204 ◽

1966 ◽

Vol 26 (2) ◽

pp. 225-236 ◽

Cited By ~ 190

Author(s):

P. Bradshaw

Keyword(s):

Turbulent Mixing ◽

Initial Conditions ◽

Mixing Layer ◽

Initial Boundary ◽

Shear Layers ◽

Free Shear Layer ◽

Turbulent Mixing Layer ◽

Free Shear Layers ◽

Final Approach ◽

Reynolds Number Effects

The distance between the separation point and the final approach to a fully developed turbulent mixing layer is found to be of the order of a thousand times the momentum-deficit thickness of the initial boundary layer, whether the latter be laminar or turbulent. There are correspondingly large shifts in the virtual origin of the mixing layer, resulting in spurious Reynolds-number effects which cause considerable difficulties in tests of model jets or blunt-based bodies, and which are probably responsible for the disagreements over the influence of Mach number on the development of free shear layers. These effects are explained.

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Effects of Turbulence on the Pressure Distribution Around a Square Cylinder and Possibility of Reduction

Journal of Fluids Engineering ◽

10.1115/1.3240953 ◽

1983 ◽

Vol 105 (2) ◽

pp. 140-145 ◽

Cited By ~ 7

Author(s):

K. C. S. Kwok

Keyword(s):

Pressure Distribution ◽

Turbulent Mixing ◽

Peak Pressure ◽

Shear Layers ◽

Transverse Force ◽

Force Characteristic ◽

Square Cylinder ◽

Pressure Coefficients ◽

Prismatic Structure ◽

Scale Turbulence

When a prismatic structure is subjected to air flow, especially at small angle of wind incidence, the separated shear layers may reattach onto the streamwise surface. The turbulent mixing in the shear layers and the extrainment of fluid results in highly fluctuating and strongly negative pressures under the reattaching shear layers. Wind tunnel tests were carried out to determine the pressure distribution around a square cylinder. It was found that an increase in turbulence, in particular fine scale turbulence, significantly altered the pressure distribution, the transverse force characteristic, and hence the galloping behavior of the square cylinder. When small vanes were fitted to the corners of the cylinder, and by maintaining a vent between the vane and the corner, the magnitude of the negative mean and peak pressure coefficients under the shear layer were substantially reduced.

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