The Boundary-Layer Velocity Distribution in Turbulent Swirling Pipe Flow

1969 ◽  
Vol 91 (4) ◽  
pp. 728-733 ◽  
Author(s):  
R. G. Backshall ◽  
Fred Landis
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Axial Flow ◽  
Swirl Flow ◽  
Momentum Balance ◽  
Twisted Tape ◽  
Layer Velocity ◽  
Wall Shear

An experimental study was performed to determine the boundary-layer characteristics of an incompressible swirl flow produced by the insertion of a helically twisted tape into a pipe. The resulting flow can be approximated by a uniform axial flow with a superposed forced vortex flow. Boundary-layer velocity measurements indicate that the total velocity in this three-dimensional flow is well approximated by the universal logarithmic velocity profile. Modified axial and tangential logarithmic velocity laws have also been derived and are shown to be in good agreement with the data. The wall shear stress has to be determined either by direct velocity gradient measurements at the wall or by a modified momentum balance since pressure loss measurements do not directly lead to the correct wall shear stress.

Wall Shear Stress Inference From Two and Three-Dimensional Turbulent Boundary Layer Velocity Profiles

1973 ◽  
Vol 95 (1) ◽  
pp. 61-67 ◽  
Author(s):  
F. J. Pierce ◽  
B. B. Zimmerman
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Three Dimensional ◽  
Law Of The Wall ◽  
Layer Velocity ◽  
Wall Shear ◽  
Near Wall

A method is developed to infer a local wall shear stress from a two-dimensional turbulent boundary layer velocity profile using all near-wall data with the Spalding single formula law of the wall. The method is used to broaden the Clauser chart scheme by providing for the inclusion of data in the laminar sublayer and transition region, as well as the data in the fully turbulent near-wall flow region. For a skewed velocity profile typical of pressure driven three-dimensional turbulent boundary layer flows, the method is extended to infer a wall shear stress for a three-dimensional turbulent boundary layer. Either wall shear stress or shear velocity values are calculated for two different sets of three-dimensional experimental data, with good agreement found between calculated and experimental results.

Direct Force Wall Shear Measurements in Pressure-Driven Three-Dimensional Turbulent Boundary Layers

1982 ◽  
Vol 104 (2) ◽  
pp. 150-155 ◽  
Author(s):  
J. E. McAllister ◽  
F. J. Pierce ◽  
M. H. Tennant
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Turbulent Boundary Layers ◽  
Direct Measurements ◽  
Stress Directions ◽  
Wall Flow ◽  
Wall Shear ◽  
Pressure Driven

Unique, simultaneous direct measurements of the magnitude and direction of the local wall shear stress in a pressure-driven three-dimensional turbulent boundary layer are presented. The flow is also described with an oil streak wall flow pattern, a map of the wall shear stress-wall pressure gradient orientations, a comparison of the wall shear stress directions relative to the directions of the nearest wall velocity as measured with a typical, small boundary layer directionally sensitive claw probe, as well as limiting wall streamline directions from the oil streak patterns, and a comparison of the freestream streamlines and the wall flow streamlines. A review of corrections for direct force sensing shear meters for two-dimensional flows is presented with a brief discussion of their applicability to three-dimensional devices.

Three-Dimensional Turbulent Boundary Layer in a Rotating Helical Channel

1975 ◽  
Vol 97 (2) ◽  
pp. 197-210 ◽  
Author(s):  
A. K. Anand ◽  
B. Lakshminarayana
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Boundary Layer ◽  
Three Dimensional ◽  
Velocity Profiles ◽  
Layer Growth ◽  
Viscous Effects ◽  
Helical Channel ◽  
Wall Shear

An analytical and experimental investigation of the characteristics of a three-dimensional turbulent boundary layer in a rotating helical channel is reported in this paper. Expressions are developed for the velocity profiles in the inner layer, where the viscous effects dominate, and the outer layer, where the viscous effects are small. The prediction of boundary layer growth is based on the momentum integral technique. The analysis is valid for incompressible flow through a rotor blade row with small camber. The velocity profiles, wall shear stress and limiting streamline angles are measured inside the passages of a flat plate inducer at various radial and chordwise locations using rotating probes. The measurements are in general agreement with the predictions. Flow near the blade tip is found to be highly complex due to interaction of blade boundary layers and the annulus wall, resulting in appreciable radial inward flow as well as a defect in mainstream velocity near the midpassage. A wall shear stress correlation, which includes the effect of both Reynolds number and rotation parameter, is derived from the measured data.

Wall Shear Stress Inference for Three-Dimensional Turbulent Boundary-Layer Velocity Profiles

1976 ◽  
Vol 43 (1) ◽  
pp. 20-27 ◽  
Author(s):  
N. Chandrashekhar ◽  
N. V. C. Swamy
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Turbulent Boundary Layers ◽  
Wall Region ◽  
Stress Components ◽  
Layer Velocity ◽  
Wall Shear ◽  
Flow Similarity ◽  
Simplified Procedure

Based on flow similarity in the near-wall region of three-dimensional turbulent boundary layers, three methods have been developed for the prediction of the wall shear stress components, their resultant and its direction. The results from all the methods agree with one another and with available experimental results. It is found that the direction of the wall shear stress vector is not the same as the direction of the limiting wall streamline, except for small crossflows. A simplified procedure for estimating skin friction is also given, by which graphical work, as in the Clauser scheme, is eliminated.

scholarly journals Bicuspid Aortic Cusp Fusion Morphology Alters Aortic Three-Dimensional Outflow Patterns, Wall Shear Stress, and Expression of Aortopathy

Circulation ◽  
2014 ◽  
Vol 129 (6) ◽  
pp. 673-682 ◽  
Author(s):  
Riti Mahadevia ◽  
Alex J. Barker ◽  
Susanne Schnell ◽  
Pegah Entezari ◽  
Preeti Kansal ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Aortic Cusp ◽  
Wall Shear

On the Effects of a Flexible Structure on Boundary Layer Stability and Transition

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Ashraf Al Musleh ◽  
Abdelkader Frendi
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Young Modulus ◽  
Boundary Layer Transition ◽  
Beam Equation ◽  
Flexible Structure ◽  
Boundary Layer Stability ◽  
Wall Shear ◽  
Fluid Wall Shear Stress

Delaying the onset of boundary layer transition has become a major research area in the last few years. This delay can be achieved by either active or passive control techniques. In the present paper, the effects of flexible or compliant structures on boundary layer stability and transition is studied. The Orr-Sommerfeld equation coupled to a beam equation representing the flexible structure is solved for a Blasius type boundary layer. A parametric study consisting of the beam thickness and material properties is carried out. In addition, the effect of fluid wall shear stress on boundary layer stability is analyzed. It is found that high density and high Young modulus materials behave like rigid structures and therefore do not alter the stability characteristic of the boundary layer. Whereas low density and low Young modulus materials are found to stabilize the boundary layer. High values of fluid wall shear stress are found to destabilize the boundary layer. Our results are in good agreement with those published in the literature.

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