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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Water engineering : Parallel jet interactions due to the gate piers
Parallel jet interactions due to the gate piers
Author : M. BIJANKHAN(1), S. KOUCHAKZADEH(2) & G. BELAUD(3)
ABSTRACT
Due to construction, operation, and maintenance difficulties, usually installing very wide gates in open channels is not
recommended. Instead, multiple parallel gates are used, which generate parallel jets. For maintenance and control
reasons, when a low flow needs to be passed, it is frequent to see only some of the gates under operation. In such
circumstances the jet width would be smaller than the downstream pool width, and consequently, a highly non-uniform
velocity distribution with longitudinal vortices would be formed in the downstream pool. The flow structure and the
submergence conditions may also be affected by the piers installed to support the gates. In this study, two gates were
considered in parallel for which only one of them was under operation. Measurements were done for different openings
and discharges, focusing on the distinguishing conditions and flow structure of the downstream jet. In the configuration
without piers, it was shown that the submergence conditions were largely affected compared to the mostly studied
configuration, basically two-dimensional, where the jet has the same width as the downstream pool. This was due to the
interaction of the jet with the dead zone behind the closed gate, involving strongly three dimensional effects, increased
head loss and friction forces. Then the effect of the separating piers was investigated experimentally. ADV measurements
were done in the downstream pool to compare the velocity distribution with and without the separating piers. This
suggests corrections of the momentum calculation in the downstream pool due to the asymmetrical jet configuration. The
results of this study can be used to calculate the submergence threshold with and without the gate piers based on the
momentum balance.
File Size : 718,375 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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