New Zealand Journal of Marine and Freshwater Research abstracts
Silverstream eco-hydraulics flume: hydraulic design and tests
V. I. NIKORA
D. G. GORING
B. J. F. BIGGS
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 8602
Christchurch, New Zealand
Abstract Hydraulic design details are presented of the
Silverstream eco-hydraulics flume, which is a 12 m long by 75 cm wide
tilting outdoor flume situated on the left bank of the Silverstream River,
30 km north of Christchurch, New Zealand. Results of testing, both
mechanical and hydraulic, are presented and discussed. The mechanical
adjustments required to accommodate the weight of water in the flume and
thermal expansion and contraction of the frame (exacerbated by being outside)
are described. Hydraulic calibration experiments using Acoustic Doppler
Velocimetry indicate that there is a central portion at least 4 m long by
15-20 cm wide of the flume where the flow is uniform and 2-dimensional.
Regions up stream and down stream of this area are affected by entrance and
exit conditions. Close to the side walls, cells of helical secondary currents
were found, and these appear to be separated from the zone of 2-dimensional
flow by narrow regions with anomalous turbulence properties. The "frozen"
turbulence hypothesis was proven true by the calibration experiments. These
findings can have implications in eco-hydraulic experiments on organism-flow
interactions, mass transfer, and uptake processes.
Keywords laboratory flumes; benthic ecology; open-channel
flow; turbulence; secondary currents
M98004
Received 4 February 1998; accepted 29 July 1998
PDF file of entire paper: medium quality (1953K); (scanned from paper original: notes about this process)
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