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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Water engineering : Intrusive measurement evaluation for sediment-laden flows interacting with an obstacle
Intrusive measurement evaluation for sediment-laden flows interacting with an obstacle
Author : RICHARD I WILSON(1), HEIDE FRIEDRICH(2) & CRAIG STEVENS(3)
ABSTRACT
The interaction of sediment-laden flows with obstacles is a growing area of research. Sediment-laden flows are also
commonly known as turbidity currents, Due to practical limitations, there are minimal experimental data available on the
spatio-temporal distribution of velocity and sediment concentration fields of currents passing an obstacle. For this study,
an instrumental rack consisting of an array of UVP transducers and siphons is used to measure velocity and density
characteristics of turbidity currents and their interaction with a rectangular obstacle. Tests are conducted for a range of
different transducer rack arrangements to determine whether their intrusive components have a significant influence on
fluid flow. Lock-exchange initiated gravity currents comprised of kaolinite and glass microspheres are released in a 400
mm wide, 5000 mm long Perspex flume, filled with ambient water to an upstream depth of 300 mm. Detailed velocity
contours plots surrounding the obstacle and instrument racks are obtained for each testing condition. Results show that
immediately after colliding with the obstacle, the current varied in velocity distribution for all tests. It was concluded that
this was likely due to the locally unpredictable nature of unsteady structures formed, rather than rack instrumental
influence. Differences in velocity distributions converged to a point where all tests showed nearly identical distributions
once the current head had passed the obstacle. It is therefore recommended that in future tests a recording time window
of at least 20 s from collision of the current with the obstacle should be implemented. The proposed instrument
arrangement is suitable for studying the effect of obstacles for passing currents, and ensures the obstacle effect
dominates the signal.
File Size : 1,635,064 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Water engineering
Date Published : 18/08/2015
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