Features of a developing turbulent boundary layer measured in a bounded flow

1979 ◽  
Vol 57 (3) ◽  
pp. 477-485 ◽  
Author(s):  
J. K. Reichert ◽  
R. S. Azad
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Physical Mechanism ◽  
Interaction Mechanism ◽  
Turbulent Boundary Layers ◽  
Layer Growth ◽  
Developing Flow ◽  
Boundary Layer Growth ◽  
Flatness Factor

Experimental results are presented for turbulence intensities, correlations, skewness of u, ∂u/∂t. boundary layer growth, flatness factor of u, and intermittency for the bounded developing flow in the inlet region of a pipe (Re = 54 900). The results exhibit several unique features which are not observed for unbounded or flat plate turbulent boundary layers. A hypothetical physical mechanism accounting for the findings is offered which suggests that, for bounded flows, an exaggerated interaction occurs at the interface between the constrained core fluid and the surrounding, growing turbulent boundary layer. This hypothetical interaction mechanism could account for the nonasymptotic development of bounded flows and it is suggested that a more detailed study using interface conditioned sampling measurements is warranted.

An Integral Method for Turbulent Boundary Layers on Rotating Disks

1993 ◽  
Vol 115 (4) ◽  
pp. 614-619 ◽  
Author(s):  
S. Abrahamson ◽  
S. Lonnes
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Integral Method ◽  
Radial Profile ◽  
Tangential Velocity ◽  
Turbulent Boundary Layers ◽  
Similarity Solutions ◽  
Layer Growth ◽  
Rotating Disks ◽  
Boundary Layer Growth

An integral method for computing turbulent boundary layers on rotating disks has been developed using a power law profile for the tangential velocity and a new model for the radial profile. A similarity solution results from the formulation. Radial transport, boundary layer growth, and drag on the disk were computed for the case of a forced vortex frees tream flow. The results were compared to previous similarity solutions. The method was extended to a Rankine vortex freestream flow. Differential equations for boundary layer parameters were developed and solved for different Reynolds numbers to look at the net entrainment, boundary layer growth, and drag on the disk.

The Prediction of Turbulent Boundary Layer Parameters in Conical Diffuser Flows

1974 ◽  
Vol 25 (3) ◽  
pp. 199-209
Author(s):  
N E A Wirasinghe ◽  
R S Neve
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Empirical Data ◽  
Turbulent Boundary Layers ◽  
Layer Growth ◽  
Pressure Gradients ◽  
Conical Diffuser ◽  
Semi Empirical ◽  
Boundary Layer Growth

SummaryThe methods suggested by Ross and by Fraser for dealing with turbulent boundary layers in adverse pressure gradients using semi-empirical data are extended to the prediction of boundary layer growth in conical diffusers, the new method making no recourse to measured static pressures, as previously required. Predictions agree closely with published experimental data by Fraser and give some justification for the use of the Ross model for the turbulent boundary layer in a diffuser provided that the diffuser is not too long and that the inlet boundary layer is thin.

The Effect of Surface Roughness and Favorable Pressure Gradient on Turbulent Boundary Layers

2011 ◽  
Author(s):  
Ju Hyun Shin ◽  
Seung Jin Song
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Flat Plate ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Layer Growth ◽  
Rough Wall ◽  
Favorable Pressure Gradient

Rough wall turbulent boundary layers subjected to pressure gradient have engineering interest for many fluid machinery applications. A number of investigations have been made to understand surface roughness and pressure gradient effects on turbulent boundary layer characteristics, but separately. In this paper, turbulent boundary layers over a flat plate with surface roughness and favorable pressure gradient (FPG) are experimentally investigated. Boundary layers in different streamwise locations were measured using boundary layer type hot-wire anemometry. Rough wall zero pressure gradient (ZPG) turbulent boundary layers were also measured to compare the result from the investigation. The surface roughness was applied by attaching sandpapers on the flat plate. The magnitude of surface roughness is representative of land-based gas turbine compressor blade. Pressure gradient was adjusted using movable endwall of the test section. Results from the measurement show characteristics of the turbulent boundary layer growth affected by both surface roughness and favorable pressure gradient.

Prediction of Turbulent Boundary Layer Development in Conical Diffusers

1966 ◽  
Vol 8 (4) ◽  
pp. 426-436 ◽  
Author(s):  
A. D. Carmichael ◽  
G. N. Pustintsev
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Shape Factor ◽  
Turbulent Boundary Layers ◽  
Energy Deficit ◽  
Momentum Thickness ◽  
Boundary Layer Development ◽  
Layer Development

Methods of predicting the growth of turbulent boundary layers in conical diffusers using the kinetic-energy deficit equation were developed. Three different forms of auxiliary equations were used. Comparison between the measured and predicted results showed that there was fair agreement although there was a tendency to underestimate the predicted momentum thickness and over-estimate the predicted shape factor.

Velocity Profiles of Turbulent Boundary Layers

1969 ◽  
Vol 73 (698) ◽  
pp. 143-147 ◽  
Author(s):  
M. K. Bull
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Boundary Layers ◽  
Experimental Work ◽  
Constant Pressure ◽  
Velocity Profiles ◽  
Turbulent Boundary Layers ◽  
Boundary Layer Equations

Although a numerical solution of the turbulent boundary-layer equations has been achieved by Mellor and Gibson for equilibrium layers, there are many occasions on which it is desirable to have closed-form expressions representing the velocity profile. Probably the best known and most widely used representation of both equilibrium and non-equilibrium layers is that of Coles. However, when velocity profiles are examined in detail it becomes apparent that considerable care is necessary in applying Coles's formulation, and it seems to be worthwhile to draw attention to some of the errors and inconsistencies which may arise if care is not exercised. This will be done mainly by the consideration of experimental data. In the work on constant pressure layers, emphasis tends to fall heavily on the author's own data previously reported in ref. 1, because the details of the measurements are readily available; other experimental work is introduced where the required values can be obtained easily from the published papers.

Equilibrium-Turbulent Boundary Layer Prediction for a Proposed Prandtl Mixing Length Distribution

1968 ◽  
Vol 10 (5) ◽  
pp. 426-433 ◽  
Author(s):  
F. C. Lockwood
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Length Distribution ◽  
Momentum Equation ◽  
Turbulent Boundary Layers ◽  
Mixing Length ◽  
Good Agreement

The momentum equation is solved numerically for a suggested ramp variation of the Prandtl mixing length across an equilibrium-turbulent boundary layer. The predictions of several important boundary-layer functions are compared with the equilibrium experimental data. Comparisons are also made with some recent universal recommendations for turbulent boundary layers since the equilibrium experimental data are limited. Good agreement is found between the predictions, the experimental data, and the recommendations.

Compressibility and Variable Density Effects in Turbulent Boundary layers

2006 ◽  
Vol 129 (4) ◽  
pp. 441-448 ◽  
Author(s):  
Kunlun Liu ◽  
Richard H. Pletcher
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Wall Temperature ◽  
Stokes Equations ◽  
Variable Density ◽  
Turbulent Boundary Layers ◽  
Reynolds Analogy ◽  
Density Effects

Two compressible turbulent boundary layers have been calculated by using direct numerical simulation. One case is a subsonic turbulent boundary layer with constant wall temperature for which the wall temperature is 1.58 times the freestream temperature and the other is a supersonic adiabatic turbulent boundary layer subjected to a supersonic freestream with a Mach number 1.8. The purpose of this study is to test the strong Reynolds analogy (SRA), the Van Driest transformation, and the applicability of Morkovin’s hypothesis. For the first case, the influence of the variable density effects will be addressed. For the second case, the role of the density fluctuations, the turbulent Mach number, and dilatation on the compressibility will be investigated. The results show that the Van Driest transformation and the SRA are satisfied for both of the flows. Use of local properties enable the statistical curves to collapse toward the corresponding incompressible curves. These facts reveal that both the compressibility and variable density effects satisfy the similarity laws. A study about the differences between the compressibility effects and the variable density effects associated with heat transfer is performed. In addition, the difference between the Favre average and Reynolds average is measured, and the SGS terms of the Favre-filtered Navier-Stokes equations are calculated and analyzed.

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