Turbulence measurements in a compressible boundary layer subjected to a shock-wave-induced adverse pressure gradient

1973 ◽  
Author(s):  
W. ROSE
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Compressible Boundary Layer ◽  
Turbulence Measurements ◽  
Wave Induced

Reynolds-shear-stress measurements in a compressible boundary layer within a shock-wave-induced adverse pressure gradient

1974 ◽  
Vol 65 (1) ◽  
pp. 177-188 ◽  
Author(s):  
W. C. Rose ◽  
M. E. Childs
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Shear Stress ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Adverse Pressure Gradient ◽  
Turbulent Heat Transfer ◽  
Shear Stresses ◽  
Turbulent Heat ◽  
Wave Induced

The results of an experimental investigation of the mean- and fluctuating-flow properties of a compressible turbulent boundary layer in a shock-wave-induced adverse pressure gradient are presented. The turbulent boundary layer developed on the wall of an axially symmetric nozzle and test section whose nominal free-stream Mach number and boundary-layer-thickness Reynolds number were 4 and 105, respectively. The adverse pressure gradient was induced by an externally generated, conical shock wave.Mean and time-averaged fluctuating-flow data, including the experimental Reynolds shear stresses and experimental turbulent heat-transfer rates, are presented for the boundary layer and external flow, upstream, within and downstream of the pressure gradient. The turbulent mixing properties of the flow were determined experimentally with a hot-wire anemometer. The calibration of the wires and the interpretation of the data are discussed.From the results of the investigation, it is concluded that the shock-wave/boundary-layer interaction significantly alters the shear-stress characteristics of the boundary layer.

Experimental Investigation of a Turbulent Compressible Boundary Layer

2009 ◽  
Author(s):  
Todd Reedy
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Pressure Gradient ◽  
Static Pressure ◽  
Adverse Pressure Gradient ◽  
Velocity Profiles ◽  
Experimental Results ◽  
Compressible Boundary Layer ◽  
Law Of The Wall ◽  
Displacement Thickness

A turbulent compressible boundary layer in a nominally Mach 4.2 flow was investigated experimentally. Pitot, wall-static pressure, total pressure and temperature measurements were utilized to determine Mach number, temperature, and velocity profiles within the boundary layer. An adverse pressure gradient was observed, resulting in non-uniform flow in the streamwise direction of the test section during development. Alterations were made to the tunnel top and bottom walls to account for the growing boundary layer displacement thickness, resulting in a much improved, uniform Mach number in the freestream and boundary layer. The existence of a slight adverse pressure gradient remained. Flow visualization was conducted via the Schlieren imaging technique. Experimental results were compared against turbulent compressible flow theory and were found to be in excellent agreement, based on an extension of the law-of-the-wall and law-of-the-wake. Velocity profiles and boundary layer thicknesses of the theoretical and experimental results aligned satisfactorily.

Turbulent-boundary-layer development in an adverse pressure gradient after an interaction with a normal shock wave

1985 ◽  
Vol 154 ◽  
pp. 43-62 ◽  
Author(s):  
W. H. Schofield
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Weak Interactions ◽  
Adverse Pressure Gradient ◽  
Major Effect ◽  
Normal Shock ◽  
Pressure Gradients ◽  
Normal Shock Wave

An experimental study has been made of the development of a turbulent boundary layer in an adverse pressure gradient after an interaction with a normal shock wave that was strong enough to separate the boundary layer locally. The pressure gradient applied to the layer was additional to the pressure gradients induced by the shock wave. Measurements were taken for several hundreds of layer thicknesses downstream of the interaction. To separate the effects of shock wave and pressure gradient a second set of observations were made in a reference layer that developed in the same adverse pressure gradient without first interacting with a normal shock wave. It is shown that the adverse pressure gradient impressed on the flow downstream of the shock has a major effect on the structure of the interaction region and the growth of the layer through it. Consequently, existing results for interactions without a postshock pressure gradient should not be used as a model for predicting practical flows, which typically have strong pressure gradients applied downstream of the shock wave. It is also shown that the shock wave produces a pronounced stabilizing effect on the downstream flow, which can be attributed to the streamwise vortices shed into the flow from the separated region formed by the shock wave. The implications of this result for nominally two-dimensional flow situations and to flows involving weak interactions without local separations are discussed.

Approximate Analytical Solution of Magnetohydrodynamics Compressible Boundary Layer flow with Pressure Gradient and suction/injection

2014 ◽  
Vol 6 (3) ◽  
pp. 1216-1226
Author(s):  
Sathyanarayana. S. B
Keyword(s):  
Boundary Layer ◽  
Analytical Solution ◽  
Pressure Gradient ◽  
Boundary Layer Flow ◽  
Exact Analytical Solution ◽  
Adverse Pressure Gradient ◽  
Compressible Boundary Layer ◽  
Analysis Method ◽  
Homotopy Analysis ◽  
Layer Flow

The aim of this work is to obtain exact analytical solution to the two dimensional laminar compressible boundary layer flow with an adverse pressure gradient in the presence of heat and mass transfer with MHD. The method applied is homotopy analysis method. It is shown that this solution agrees very well with numerical solution which is obtained by Runge-Kutta Merson method and results are shown graphically for different magnetic parameters.

Boundary Layer Flashback Model for Hydrogen Flames in Confined Geometries Including the Effect of Adverse Pressure Gradient

2020 ◽  
Author(s):  
Ólafur H. Björnsson ◽  
Sikke A. Klein ◽  
Joeri Tober
Keyword(s):  
Boundary Layer ◽  
Pressure Gradient ◽  
Flow Separation ◽  
Gradient Flow ◽  
Lewis Number ◽  
Adverse Pressure Gradient ◽  
Future Research ◽  
Diffuser Flow ◽  
Combustion Properties ◽  
Quenching Distance

Abstract The combustion properties of hydrogen make premixed hydrogen-air flames very prone to boundary layer flashback. This paper describes the improvement and extension of a boundary layer flashback model from Hoferichter [1] for flames confined in burner ducts. The original model did not perform well at higher preheat temperatures and overpredicted the backpressure of the flame at flashback by 4–5x. By simplifying the Lewis number dependent flame speed computation and by applying a generalized version of Stratford’s flow separation criterion [2], the prediction accuracy is improved significantly. The effect of adverse pressure gradient flow on the flashback limits in 2° and 4° diffusers is also captured adequately by coupling the model to flow simulations and taking into account the increased flow separation tendency in diffuser flow. Future research will focus on further experimental validation and direct numerical simulations to gain better insight into the role of the quenching distance and turbulence statistics.

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