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.

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.

Thermal Turbulent Boundary Layer Under Strong Adverse Pressure Gradient Near Separation

1982 ◽  
Vol 104 (3) ◽  
pp. 397-402 ◽  
Author(s):  
N. Afzal
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Thermal Boundary Layer ◽  
Adverse Pressure Gradient ◽  
Power Laws ◽  
Wall Layer ◽  
Pressure Gradients ◽  
Boundary Layer Problem ◽  
Half Power ◽  
Layer Problem

The problem of the thermal turbulent boundary layer under the influence of strong adverse pressure gradients near separation is analysed by the method of matched asymptotic expansions. The limit corresponding to the neighborhood of separation, as formulated by Afzal [3], is employed. The thermal boundary layer problem is analysed using the appropriate inner and outer expansions (both above the thermal wall layer). It is found by matching that there exists an inertial sublayer where temperature distribution obeys the inverse half power laws. The comparison of the theory with the measurement shows that the slope and intercept of the wall (inner) law may be regarded as universal numbers, whereas the intercept of outer law shows a linear dependence on τw/δpx.

Transonic Normal Shock-Turbulent Boundary Layer Interaction in Pressure Gradient Flows

1977 ◽  
Author(s):  
A. G. Panaras ◽  
G. R. Inger
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Normal Shock ◽  
Pressure Gradients ◽  
Local Boundary ◽  
Boundary Layer Interaction ◽  
Theoretical Predictions ◽  
Disturbance Analysis ◽  
Separating Flows

A basic theoretical analysis of the interaction of a transonic normal shock wave with a non-separating turbulent boundary layer in a background pressure gradient is given. The method is based on an extension of Inger and Mason’s small disturbance analysis to account for both explicit pressure gradients upstream and downstream of the interaction and the implicit pressure gradient effects on the local boundary layer shape plus the back-effect of the interaction-induced boundary layer thickness growth (blockage) that is important in channel flows and turbomachinery applications. The theory predicts the detailed disturbance pressure and skin friction distributions, including lateral pressure gradients, and is readily imbedded locally in a global calculation scheme involving transonic inviscid and boundary layer prediction codes upstream and downstream of the shock. Good agreement is found between the resulting theoretical predictions and experimental results for non-separating flows.

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

Adiabatic Wall Effectiveness of a Turbulent Boundary Layer With Slot Injection

1976 ◽  
Vol 98 (2) ◽  
pp. 240-244 ◽  
Author(s):  
R. E. Mayle ◽  
F. C. Kopper
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Free Stream ◽  
Theoretical Work ◽  
Layer Growth ◽  
Stream Velocity ◽  
Adiabatic Wall ◽  
Velocity Flow ◽  
Hydrodynamic Boundary Layer ◽  
Boundary Layer Growth

An analysis is presented which extends the theoretical work of Weighardt and determines the adiabatic wall effectiveness of a turbulent boundary layer in a constant free-stream velocity flow heated or cooled by the discharge of a secondary fluid through a slot. A comparison of the analysis with the experimental results of Wieghardt is made and it is found that the streamwise decay in adiabatic wall effectiveness, except in the immediate region of the slot, may be explained by considering the thermal boundary layer growth within the hydrodynamic boundary layer.

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.

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