The Shape-Factor Relationship for Turbulent Boundary Layers

1983 ◽  
Vol 34 (2) ◽  
pp. 147-161 ◽  
Author(s):  
M.M.M. El Telbany ◽  
J. Niknejad ◽  
A.J. Reynolds
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Shape Factor ◽  
Factor H ◽  
Boundary Layer Development ◽  
The Common ◽  
Modified Formula ◽  
The Relationship ◽  
Layer Development ◽  
Common Shape

SummaryConsideration is given to the relationship H1 = f(H) linking the common shape factor H and the mass-flow shape parameter H1 which is used in entrainment models of boundary-layer development. A formula suggested by Green et al is found to be most nearly consistent with the measurements presented. However, a more exact prediction of H1 is obtained by introducing a factor involving the Reynolds number based on the local momentum thickness θ; thus H1 = f(H, Reθ). Predictions obtained by incorporating the appropriately modified entrainment equation into the well-known method of Green et al prove not to give an improved representation of the development of boundary layers studied experimentally by the authors and others. It is concluded that the modified formula for H1 is primarily useful in giving an improved specification of the overall boundary layer thickness δ = θ(H1 + H), and hence of other features of the developing profile.

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.

Endwall Boundary Layer Development in a Multistage Low-Speed Compressor With Tandem Stator Vanes

2021 ◽  
Author(s):  
Michael Hopfinger ◽  
Volker Gümmer
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Shear Stresses ◽  
Flow Area ◽  
Stage Design ◽  
Low Speed ◽  
Boundary Layer Development ◽  
Viscous Shear ◽  
Layer Development ◽  
Highly Loaded

Abstract The development of viscous endwall flow is of major importance when considering highly-loaded compressor stages. Essentially, all losses occurring in a subsonic compressor are caused by viscous shear stresses building up boundary layers on individual aerofoils and endwall surfaces. These boundary layers cause significant aerodynamic blockage and cause a reduction in effective flow area, depending on the specifics of the stage design. The presented work describes the numerical investigation of blockage development in a 3.5-stage low-speed compressor with tandem stator vanes. The research is aimed at understanding the mechanism of blockage generation and growth in tandem vane rows and across the entire compressor. Therefore, the blockage generation is investigated as a function of the operating point, the rotational speed and the inlet boundary layer thickness.

An Approach to Three-Dimensional Turbulent Boundary Layers

1966 ◽  
Author(s):  
A. D. Carmichael
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Shape Factor ◽  
Basic Assumption ◽  
Three Dimensional ◽  
Cross Flow ◽  
Turbulent Boundary Layers ◽  
Factor H ◽  
Simple Method ◽  
The Cross

A relatively simple method for predicting some of the characteristics of three-dimensional turbulent boundary layers is presented. The basic assumption of the method is that the cross-flow is small. An empirical correlation of a basic shape factor of the cross-flow boundary layer against the streamwise shape factor H is provided. This correlation, together with data for the streamwise boundary layer, is used to predict the cross flow. The solution is very sensitive to the accuracy of the streamwise boundary-layer data which is predicted by conventional two-dimensional methods.

Turbulent Boundary Layers in Diffusers Exhibiting Partial Stall

1967 ◽  
Vol 89 (3) ◽  
pp. 655-663 ◽  
Author(s):  
H. L. Moses ◽  
J. R. Chappell
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Internal Flow ◽  
Separated Flow ◽  
Boundary Layer Separation ◽  
Simple Analytical Model ◽  
One Dimensional ◽  
Layer Separation ◽  
Boundary Layer Development ◽  
Layer Development

An investigation of turbulent boundary-layer separation in internal flow is presented, with experimental results for a variable angle, two-dimensional diffuser. A simple analytical model is adopted, which consists of wall boundary layers and a one-dimensional, inviscid core. By calculating the pressure simultaneously with the boundary-layer development, the approximate method is extended to include the separated region. With a limited amount of separated flow, the calculated pressure recovery agrees reasonably well with the experiments and gives a fair indication of maximum diffusion performance. The limitation of the model, as well as the possibility of singularities and downstream instability, are discussed in relation to the general problem of boundary-layer separation.

Boundary Layer Development in Axial Compressors and Turbines: Part 4 of 4 — Computations and Analyses

1995 ◽  
Author(s):  
David E. Halstead ◽  
David C. Wisler ◽  
Theodore H. Okiishi ◽  
Gregory J. Walker ◽  
Howard P. Hodson ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Axial Compressors ◽  
Boundary Layer Development ◽  
Computational Analyses ◽  
Layer Development ◽  
Detailed Picture ◽  
Computational Predictions

This is Part Four of a four-part paper. It begins with Section 16.0 and concludes the description of the comprehensive experiments and computational analyses that have led to a detailed picture of boundary layer development on airfoil surfaces in multistage turbomachinery. In this part the computational predictions made using several modem boundary layer codes are presented. Both steady codes and an unsteady code were evaluated. The results are compared with time-averaged and unsteady integral parameters measured for the boundary layers. Assessments are made to provide guidance in using the predictive codes to locate transition and predict loss. Conclusions from the entire work are then presented.

Boundary Layer Development in Axial Compressors and Turbines: Part 4 of 4—Computations and Analyses

1997 ◽  
Vol 119 (1) ◽  
pp. 128-139 ◽  
Author(s):  
D. E. Halstead ◽  
D. C. Wisler ◽  
T. H. Okiishi ◽  
G. J. Walker ◽  
H. P. Hodson ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Axial Compressors ◽  
Boundary Layer Development ◽  
Computational Analyses ◽  
Layer Development ◽  
Detailed Picture ◽  
Computational Predictions

This is Part Four of a four-part paper. It begins with Section 16.0 and concludes the description of the comprehensive experiments and computational analyses that have led to a detailed picture of boundary layer development on airfoil surfaces in multistage turbomachinery. In this part, the computational predictions made using several modern boundary layer codes are presented. Both steady codes and an unsteady code were evaluated. The results are compared with time-averaged and unsteady integral parameters measured for the boundary layers. Assessments are made to provide guidance in using the predictive codes to locate transition and predict loss. Conclusions from the computational analyses are then presented.

Stabilizing and Destabilizing Effects of Coriolis Force on Two-Dimensional Laminar and Turbulent Boundary Layers

1979 ◽  
Vol 101 (1) ◽  
pp. 23-29 ◽  
Author(s):  
H. Koyama ◽  
S. Masuda ◽  
I. Ariga ◽  
I. Watanabe
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Coriolis Force ◽  
Stable Boundary Layer ◽  
Numerical Evaluation ◽  
Critical Reynolds Number ◽  
Turbulent Boundary Layers ◽  
Two Dimensional ◽  
Boundary Layer Development ◽  
Layer Development

To investigate the effects of Coriolis force on two-dimensional laminar and turbulent boundary layers, quantitative experiments were performed. A numerical evaluation was also carried out utilizing the Monin-Oboukhov coefficient including the effect of rotation. From the experimental results, the boundary layer development was found to be promoted on the unstable side and suppressed on the stable side, in comparison with the case of zero-rotation. In the stable boundary layer, the critical Reynolds number for relaminarization was observed to increase as rotation number was decreased. Calculated results were seen to predict the stabilizing effect of Coriolis force fairly well.

Turbulent Boundary-Layer Development on a Two-Dimensional Aerofoil with Supercritical Flow at low Reynolds Number

1982 ◽  
Vol 33 (2) ◽  
pp. 174-198 ◽  
Author(s):  
C.J. Baker ◽  
L.C. Squire
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Layers ◽  
Turbine Blade ◽  
Side Wall ◽  
Two Dimensional ◽  
Supercritical Flow ◽  
Boundary Layer Development ◽  
Wide Range ◽  
Layer Development

SummaryDetailed measurements have been made of the boundary-layer development on a small two-dimensional aerofoil with supercritical flow and a weak shock wave, together with similar measurements on the tunnel side wall opposite the aerofoil surface. The Reynolds number of the test is similar to that found in the turbines of jet engines and there is a strong favourable pressure gradient ahead of the interaction of the shock with the boundary layer as often occurs in turbine blade passages. However, whereas the boundary layer on the aerofoil is thin and of the same thickness as that on a turbine blade, the thicker boundary layer on the wall is more typical of that on the hub or casing. The experimental results are compared with results from a wide range of calculation methods. One interesting conclusion from these comparisons is the fact that prediction methods which perform well for the thin boundary layers on the aerofoil do not necessarily perform as well for the thicker boundary layers on the wall.

Compressor Blade Boundary Layers: Part 2 — Measurements With Incident Wakes

1989 ◽  
Author(s):  
Y. Dong ◽  
N. A. Cumpsty
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Transition Process ◽  
Compressor Blade ◽  
Momentum Thickness ◽  
Trailing Edge ◽  
Boundary Layer Development ◽  
Blade Row ◽  
Layer Development

This paper follows directly from Part I** by the same authors and describes measurements of the boundary layer on a supercritical-type compressor blade with wakes from a simulated moving upstream blade row convected through the passage. (The blades and the test facilities togehter with the background are described in Part I.) The results obtained with the wakes are compared to those with none for both low and high levels of inlet turbulence. The transition process and boundary layer development is very different in each case though the overall momentum thickness at the trailing edge is fairly similar. None of the models for transition is satisfactory when this is initiated by moving wakes.

Compressor Blade Boundary Layers: Part 2—Measurements With Incident Wakes

1990 ◽  
Vol 112 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Y. Dong ◽  
N. A. Cumpsty
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Transition Process ◽  
Compressor Blade ◽  
Momentum Thickness ◽  
Trailing Edge ◽  
Boundary Layer Development ◽  
Blade Row ◽  
Layer Development

This paper follows directly from Part 1 by the same authors and describes measurements of the boundary layer on a supercritical-type compressor blade with wakes from a simulated moving upstream blade row convected through the passage. (The blades and the test facilities together with the background are described in Part 1). The results obtained with the wakes are compared to those with none for both low and high levels of inlet turbulence. The transition process and boundary layer development are very different in each case, though the overall momentum thickness at the trailing edge is fairly similar. None of the models for transition is satisfactory when this is initiated by moving wakes.

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