Further Investigation of the Near Wall Flow Structure of a Low Reynolds Number 3-D Turbulent Boundary Layer
Author : J. L. Fleming
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Page : pages
File Size : 15,67 MB
Release : 1995
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Author : J. L. Fleming
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Page : pages
File Size : 15,67 MB
Release : 1995
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Author : J. L. Fleming
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Page : pages
File Size : 34,76 MB
Release : 1994
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Author : Jonathan Lee Fleming
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Page : 522 pages
File Size : 31,29 MB
Release : 1996
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Author : Jonathan Lee Fleming
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Page : 0 pages
File Size : 43,10 MB
Release : 1996
Category :
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Laser Doppler velocimetry (LDV) measurements and hydrogen bubble flow visualization techniques were used to examine the near-wall flow structure of 2D and 3D turbulent boundary layers (TBLs) over a range of low Reynolds numbers. The goals of this research were (1) an increased understanding of the flow physics in the near wall region of turbulent boundary layers, (2) to observe and quantify differences between 2D and 3D TBL flow structures, and (3) to document Reynolds number effects for 3D TBLs. The LDV data have provided results detailing the turbulence structure of the 2D and 3D TBLs. These results include mean Reynolds stress distributions, flow skewing results, and U and V spectra. Effects of Reynolds number for the 3D flow were also examined. Comparison to results with the same 3D flow geometry but at a significantly higher Reynolds number provided unique insight into the structure of 3D TBLs. While the 3D mean and fluctuating velocities were found to be highly dependent on Reynolds number, a previously defined shear stress parameter was discovered to be invariant with Reynolds number. The hydrogen bubble technique was used as a flow visualization tool to examine the near-wall flow structure of 2D and 3D TBLs. Both the quantitative and qualitative results displayed larger turbulent fluctuations with more highly concentrated vorticity regions for the 2D flow.
Author : James G.. Brasseur
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Page : 30 pages
File Size : 46,19 MB
Release : 1994
Category : Reynolds number
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Author : Alexander J. Smits
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Page : 50 pages
File Size : 23,65 MB
Release : 1993
Category : Reynolds number
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Author : Constantine John Strataridakis
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Page : 378 pages
File Size : 50,7 MB
Release : 1989
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Author : O. Sendstad
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Page : 130 pages
File Size : 47,67 MB
Release : 1992
Category : Simulation methods
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Author : P. W. Runstadler
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Page : 346 pages
File Size : 21,46 MB
Release : 1963
Category : Boundary layer
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A combination of visual and quantitative measurements is presented, providing a physical picture of the turbulent boundary layer flow structure on a flat plate. The flow structure is shown to consist of three zones, each zone has a one to one correspondence to the well known regions of the u+, y+ mean velocity profile. A wall layer region is shown to exist below y+ = 10. An apparently fully turbulent region exists corresponding to the logarithmic ''law of the wall'' and the ''buffer'' region. An intermittent zone appears to agree closely with the ''wake'' deviation region. An entirely new result of the investigation is the delineation of the structure of the wall layer region. This region is shown to contain a relatively regular structure of low and high velocity fluid streaks alternating in the span direction, together with the ejection of low momentum fluid into the outer flow. Correlations are given for the rate of ejection and the streak spacing. A qualitative description of other features of the wall layer region and the character of the remainder of the boundary layer flow structure is presented. (Author).
Author : J. D. A. Walker
Publisher :
Page : 184 pages
File Size : 43,98 MB
Release : 1991
Category : Boundary value problems
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In the past decade, progress has been made in determining the nature of turbulent flow near walls. Many of these advances, which have occurred through new experimental methodologies, direct numerical simulations, and new theoretical developments, are described in this volume.