Turbulence in a square channel with transverse ribs

Hot-wire measurements of the mean flow and turbulence characteristics in a square channel roughened with transverse ribs mounted on two opposing sidewalls are presented for three rib configurations: single rib, in-line multiple ribs, and staggered multiple ribs. Test conditions for multiple ribs use...

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Bibliographic Details
Published in:Climatic change 1994-01, Vol.28 (4), p.155-163
Main Authors: Rivir, Richard B, Chyu, Mingking K, Maciejewski, Paul K
Format: Article
Language:English
Subjects:
Boundary layers
Channel flow
Flow measurement
Turbulent flow
Online Access:Get full text
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Summary:Hot-wire measurements of the mean flow and turbulence characteristics in a square channel roughened with transverse ribs mounted on two opposing sidewalls are presented for three rib configurations: single rib, in-line multiple ribs, and staggered multiple ribs. Test conditions for multiple ribs use p/H identical with 10, H/D identical with 0.17, and Re identical with 23,000. Measured results highlight the spatial distribution and evolution of turbulence intensity and integral scale from the flow entrance of the first period to the developed regime near the exit of the third period. The highly turbulent, shear layer initiated near the trailing upper-edge of a rib elevates the turbulence level in the mainstream of the channel. The magnitude of turbulence intensity in the channel core rises from 0.7% in the approaching flow to about 20 - 25% near the exit of the third period. The integral scale dominating the mainstream flow increases from approximately one-half the rib-height, 0.5 H, in the approaching flow to 1.5 - 2.5 H behind the first rib and further downstream.
ISSN:0165-0009