scholarly journals Erratum to : BOTTOM SHEAR STRESS PREDICTION FOR THREE DIMENSIONAL WAVE-CURRENT BOUNDARY LAYER

1997 ◽  
Vol 1997 (565) ◽  
pp. e1-e1
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Three Dimensional ◽  
Bottom Shear Stress ◽  
Stress Prediction ◽  
Dimensional Wave

Turbulence structure of a reattaching mixing layer

1981 ◽  
Vol 110 ◽  
pp. 171-194 ◽  
Author(s):  
C. Chandrsuda ◽  
P. Bradshaw
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Reynolds Shear Stress ◽  
Mixing Layer ◽  
Three Dimensional ◽  
Flow Region ◽  
Turbulent Energy ◽  
Turbulence Structure ◽  
Hot Wire ◽  
Recirculating Flow

Hot-wire measurements of second- and third-order mean products of velocity fluctuations have been made in the flow behind a backward-facing step with a thin, laminar boundary layer at the top of the step. Measurements extend to a distance of about 12 step heights downstream of the step, and include parts of the recirculating-flow region: approximate limits of validity of hot-wire results are given. The Reynolds number based on step height is about 105, the mixing layer being fully turbulent (fully three-dimensional eddies) well before reattachment, and fairly close to self-preservation in contrast to the results of some previous workers. Rapid changes in turbulence quantities occur in the reattachment region: Reynolds shear stress and triple products decrease spectacularly, mainly because of the confinement of the large eddies by the solid surface. The terms in the turbulent energy and shear stress balances also change rapidly but are still far from the self-preserving boundary-layer state even at the end of the measurement region.

Roughness Element Geometry Required for Wind Tunnel Simulations of the Atmospheric Wind

1977 ◽  
Vol 99 (3) ◽  
pp. 480-485 ◽  
Author(s):  
I. S. Gartshore ◽  
K. A. De Croos
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Wind Tunnel ◽  
Roughness Element ◽  
Three Dimensional ◽  
Wall Stress ◽  
Wide Range ◽  
Drag Plate ◽  
Rough Boundaries ◽  
Single Figure

Using a data correlation for the wall stress associated with very rough boundaries and a semi-empirical calculation method, the shape of boundary layers in exact equilibrium with the roughness beneath them is calculated. A wide range of roughness geometries (two- and three-dimensional elements) is included by the use of equivalent surfaces of equal drag per unit area. Results can be summarized in a single figure which relates the shape factor of the boundary layer (its exponent if it has a power law velocity profile) to the height of the roughness elements and their spacing. New data for one turbulent boundary layer developing over a long fetch of uniform roughness is presented. Wall shear stress, measured directly from a drag plate is combined with boundary layer integral properties to show that the shear stress correlation adopted is reasonably accurate and that the boundary layer is close to equilibrium after passing over a streamwise roughness fetch equal to about 350 times the roughness element height. An example is given of the way in which roughness geometry may be chosen from calculated equilibrium results, for one particular boundary layer thickness and a shape useful for simulating strong atmospheric winds in a wind tunnel.

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.

scholarly journals Measurements in an incompressible three-dimensional turbulent boundary layer, under infinite swept-wing conditions, and comparison with theory

1975 ◽  
Vol 70 (1) ◽  
pp. 127-148 ◽  
Author(s):  
B. Van Den Berg ◽  
A. Elsenaar ◽  
J. P. F. Lindhout ◽  
P. Wesseling
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Turbulent Boundary Layer ◽  
Three Dimensional ◽  
Adverse Pressure Gradient ◽  
Turbulent Shear ◽  
Two Dimensional ◽  
Swept Wing ◽  
Test Plate ◽  
Turbulent Shear Stress

First a three-dimensional turbulent boundary-layer experiment is described. This has been carried out with the specific aim of providing a test-case for calculation methods. Much attention has been paid to the design of the test set-up. An infinite swept-wing flow has been simulated with good accuracy. The initially two-dimensional boundary layer on the test plate was subjected to an adverse pressure gradient, which led to three-dimensional separation near the trailing edge of the plate. Next, a calculation method for three-dimensional turbulent boundary layers is discussed. This solves the boundary-layer equations numerically by finite differences. The turbulent shear stress is obtained from a generalized version of Bradshaw's two-dimensional turbulent shear stress equation. The results of the calculations are compared with those of the experiment. Agreement is good over a considerable distance; but large discrepancies are apparent near the separation line.

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