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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Hydro-environment : Flow and turbulence structure past a dense circular patch of vegetation
Flow and turbulence structure past a dense circular patch of vegetation
Author : W. Y. CHANG (1), G. CONSTANTINESCU (2) & W. F. TSAI (3)
ABSTRACT
In the present study, flow and turbulence structure past a circular patch of emerged vegetation containing a number of
250 identical circular rigid cylinders is investigated, corresponding to a solid volume fraction SVF=0.23. Similar to most
previous laboratory studies of channels containing vegetation, the rigid plant stems are modeled as solid vertical
cylinders of diameter d=0.03D disposed in a staggered arrangement, where D is the diameter of the porous cylinder.
Eddy resolving simulations that resolve the large scale coherent structures are conducted at a Reynolds number of
20,000 defined with the channel depth h (h/D=0.45) and the bulk velocity of the fully developed incoming turbulent flow
in the channel containing the patch are conducted for the porous cylinder case (SVF=0.23) and for the corresponding
solid cylinder case (SVF=1.0). The flow past the individual cylinders (plant stems) is resolved. The paper discusses the
changes in the structure of the mean flow and turbulence within the wake region, how the bleeding flow influences the
large scale vortex shedding behind the cylinder and how the characteristics of the horseshoe vortex system forming
around the upstream face of the cylinder change with the SVF. The bed friction velocity distributions that determine the
capacity of the flow to entrain sediment within and around the patch are analyzed.
File Size : 1,853,415 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Hydro-environment
Date Published : 19/08/2015
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