Experimental Investigation of a Turbulent Boundary Layer Subject to an Adverse Pressure Gradient at $$Re_{\theta }$$ R e θ up to 10000 Using Large-Scale and Long-Range Microscopic Particle Imaging

2015 ◽  
pp. 271-281
Author(s):  
Tobias Knopp ◽  
Nicolas A. Buchmann ◽  
Daniel Schanz ◽  
Christian Cierpka ◽  
Rainer Hain ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Long Range ◽  
Large Scale ◽  
Adverse Pressure Gradient ◽  
Microscopic Particle ◽  
Particle Imaging

A supersonic turbulent boundary layer in an adverse pressure gradient

1990 ◽  
Vol 211 ◽  
pp. 285-307 ◽  
Author(s):  
Emerick M. Fernando ◽  
Alexander J. Smits
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Pressure Distribution ◽  
Large Scale ◽  
Adverse Pressure Gradient ◽  
Large Scale Structures ◽  
Streamline Curvature ◽  
The Mean ◽  
Scale Structures

This investigation describes the effects of an adverse pressure gradient on a flat plate supersonic turbulent boundary layer (Mf ≈ 2.9, βx ≈ 5.8, Reθ, ref ≈ 75600). Single normal hot wires and crossed wires were used to study the Reynolds stress behaviour, and the features of the large-scale structures in the boundary layer were investigated by measuring space–time correlations in the normal and spanwise directions. Both the mean flow and the turbulence were strongly affected by the pressure gradient. However, the turbulent stress ratios showed much less variation than the stresses, and the essential nature of the large-scale structures was unaffected by the pressure gradient. The wall pressure distribution in the current experiment was designed to match the pressure distribution on a previously studied curved-wall model where streamline curvature acted in combination with bulk compression. The addition of streamline curvature affects the turbulence strongly, although its influence on the mean velocity field is less pronounced and the modifications to the skin-friction distribution seem to follow the empirical correlations developed by Bradshaw (1974) reasonably well.

An experimental investigation of an unsteady adverse pressure gradient turbulent boundary layer: embedded shear layer scaling

2017 ◽  
Vol 815 ◽  
pp. 592-642 ◽  
Author(s):  
D. M. Schatzman ◽  
F. O. Thomas
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Shear Layer ◽  
Adverse Pressure Gradient ◽  
Local Flow ◽  
Wide Range ◽  
Scaling Parameters ◽  
High Reynolds

An experimental investigation of an unsteady adverse pressure gradient turbulent boundary layer is described. It is demonstrated that the local flow physics is largely dominated by an inflectional instability which gives rise to an embedded shear layer contained within the boundary layer. Experimental measurements are presented which are fully consistent with the presence of clockwise spanwise-oriented coherent vorticity within the embedded shear layer. Using embedded shear layer scaling parameters in the form of the shear layer vorticity thickness and the velocity defect at the upper inflection point, both the mean and the phase-averaged boundary layer velocity profiles exhibit similarity in both space and time over a large wall-normal extent. In a similar manner, the profiles of the streamwise-component turbulence intensity and Reynolds stress also exhibit similarity when scaled with the embedded shear layer parameters. The embedded shear layer scaling of previously published adverse pressure gradient turbulent boundary layer measurements confirms its generic applicability in a wide range of flow-field geometries and extending to high Reynolds numbers.

A Superposition Analysis of the Turbulent Boundary Layer in an Adverse Pressure Gradient

1951 ◽  
Vol 18 (1) ◽  
pp. 95-100
Author(s):  
Donald Ross ◽  
J. M. Robertson
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Pressure Recovery ◽  
Stress Coefficient ◽  
Wall Shear

Abstract As an interim solution to the problem of the turbulent boundary layer in an adverse pressure gradient, a super-position method of analysis has been developed. In this method, the velocity profile is considered to be the result of two effects: the wall shear stress and the pressure recovery. These are superimposed, yielding an expression for the velocity profiles which approximate measured distributions. The theory also leads to a more reasonable expression for the wall shear-stress coefficient.

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