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An experimental/analytical investigation of buoyant jets in shallow water

This thesis presents the results of an experimental
and analytical study of single-port buoyant turbulent jets
discharged into shallow water. The experimental results
include the measured downstream dilution, centerline
concentration and trajectory. Independent parameters
considered were Froude number, submerged depth, discharge
angle and velocity ratio.
Results indicate that decreasing the discharge depth
provides earlier occurrence of surface effect and greatly
decreases dilution. Dilution increases with decreasing
Froude number. Increasing the discharge angle from the
horizontal into cross current increases the dilution
ratio. The effect of ambient current on dilution depends
on the angle of discharge. For cross-flow discharges, the
dilution rate decreases with increasing ambient current,
while for co-flow discharge the reverse trend was
observed. As plumes reach the water surface, the dilution
rate increases with increasing ambient velocity. The
jets bend over rapidly for cross-flow discharges when
large ambient currents are present.
The analytical portion of this report presents an
integral method proposed by Davis (1975) for merging
multiple buoyant jets. This merging model was used to
simulate the single-port buoyant jet in shallow water.
This was done by using an image method where the submerged
depth was simulated by the spacing between images. The
entrainment function as presented by Kannberg and Davis
(1978) was used except for a modification within the zone
of merged plumes.
Comparisons of the model prediction were made with
experimental data. Results indicate that good predictions
are obtained for buoyant jets discharging at 0 and 45
degrees into shallow water by using the image method as
long as the Froude number is above 13.5. For lower Froude
number and vertical discharges, model predictions are only
fair. / Graduation date: 1991

Identiferoai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37403
Date20 November 1990
CreatorsHsiao, Entsung
ContributorsDavis, Lorin R.
Source SetsOregon State University
Languageen_US
Detected LanguageEnglish
TypeThesis/Dissertation

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