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.

A Modified Entrainment Theory for the Prediction of Turbulent Boundary Layer Growth in Adverse Pressure Gradients

1969 ◽  
Vol 91 (4) ◽  
pp. 649-655
Author(s):  
W. B. Nicoll ◽  
B. R. Ramaprian
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Layer Growth ◽  
Pressure Gradients ◽  
Shape Factors ◽  
Power Profile ◽  
Half Power ◽  
Separating Flows ◽  
Boundary Layer Growth ◽  
Two Parameter

An approach based on the “entrainment” theory is presented as a tool for the prediction of turbulent boundary layer growth in adverse pressure gradients. The rate of entrainment of free-stream fluid by the boundary layer is assumed to be a unique function of the shape factor. A two parameter velocity profile has been assumed, which reduces to the Spalding [24] profile for zero pressure gradient flows and to the half-power profile of Stratford [26] for separating flows. The integral equations of continuity and momentum are solved with the above empirical input to predict the growth of the boundary layer parameters, both in two-dimensional and axisymmetric flows. The predictions are compared with some of the available experimental data in both the cases. The technique is found to give improved predictions compared with those of previous methods. Results in the case of conical diffusers indicate that the theory predicts slightly higher shape factors than actual, especially in the far downstream portions of the diffuser and thus furnishes a slightly conservative method for design.

scholarly journals Calculation of some turbulent wall currents

2021 ◽  
Vol 1 (101) ◽  
pp. 89-93
Author(s):  
Vitalii Mamchuk ◽  
Leonid Romaniuk
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Mathematical Model ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Positive Pressure ◽  
Pressure Gradients ◽  
Turbulent Wall

A mathematical model for the calculation of turbulent boundary layers and wall stream has been developed. The results of calculations are compared with the results of other authors on the compliance of the calculated values with the experimental data. The currents that are formed under the influence of positive pressure gradients and lead to the phenomenon of separation of the turbulent boundary layer are studied.

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.

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.

A Simplified Form of the Auxiliary Equation for Use in the Calculation of Turbulent Boundary Layers

1958 ◽  
Vol 62 (567) ◽  
pp. 215-219
Author(s):  
T. J. Black
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Boundary Layers ◽  
Turbulent Boundary Layers ◽  
Auxiliary Equation ◽  
Pressure Gradients ◽  
Momentum Thickness ◽  
Form Parameter ◽  
New Type ◽  
Simple Quadrature

A New type of auxiliary equation is given for calculating the development of the form-parameter H in turbulent boundary layers with adverse pressure gradients. The chief advantage of this new method lies in the rapidity and ease of calculation which has been achieved, without apparent sacrifice of accuracy.Whereas the growth of momentum thickness in the turbulent boundary layer can now be rapidly calculated by methods involving only simple quadrature, the prediction of the form parameter development remains a laborious task, while the results obtained do not always appear to justify the complexity of the calculations.

Turbulent boundary-layer growth over a longitudinally curved surface

AIAA Journal ◽  
1975 ◽  
Vol 13 (11) ◽  
pp. 1448-1453 ◽  
Author(s):  
R. N. Meroney ◽  
P. Bradshaw
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Layer Growth ◽  
Curved Surface ◽  
Boundary Layer Growth
Sign in / Sign up

Export Citation Format

Share Document