IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 34th Congress - Brisbane (2011) : THEME 4: Responding to Shifting Water Resources : Turbulence and mean-velocity structure of flows over filamentous biofilms
Turbulence and mean-velocity structure of flows over filamentous biofilms
Author : J.M. Andrewartha1 and J.E. Sargison1
The growth of biofilms on ships and the walls of conduits causes drag penalties due to the increase in surface friction between the flow and the surface. Natural freshwater biofilms exist in different forms, including soft gelatinous slimes and filamentous streamers. The effect of filamentous biofilms on the physics of the flow and associated increases in drag was examined by developing an idealised biofilm consisting of artificial streamers, designed to mimic the filamentous component of naturally occurring biofilms. Changes to the flow structure were investigated using test plates inserted in a water tunnel fitted with a two-dimensional Laser Doppler Velocimetry system to obtain mean velocity and turbulence boundary layer profiles. Significant changes to the turbulence intensity and turbulent Reynolds stresses were measured over the entire boundary layer. The streamers also caused a thickening of the boundary layer, a 23% increase in local skin friction coefficient and increased wake strength.
File Size : 459,652 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 34th Congress - Brisbane (2011)
Article : THEME 4: Responding to Shifting Water Resources
Date Published : 01/07/2011
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