ERDC/CHL CHETN-IV-55
March 2003
dumping during the opposite tide flow often alleviated this problem. These simple experiments
revealed more efficient dredging and disposal practices that could substantially reduce the amount of
deposited dredge material re-entering the port area.
Total cost for designing, fabricating, and testing the 3-D Cook Inlet model was less than ,000.
However, this modest cost stems from the fact that bathymetry in digital form was available from a
companion numerical model study.
SUMMARY: The new precision flow table developed under the Coastal Inlets Research Program
at CHL provides an efficient and cost-effective tool for examining complex flow patterns formed by
solid boundaries such as jetties, bulkheads, groins, and rocky headlands. Flow modifications
stemming from changes in boundary or upstream configurations are easily evaluated, and this aids
project study optimization by quick identification of unsuitable alternatives. In most cases flow table
studies do not provide final design and project optimization, which should be accomplished using
more sophisticated tools such as large physical models or numerical simulations.
The flow table simulates only current flow situations; impacts due to waves are not included. Types
of studies that can be conducted with this facility include the following:
a. Visualizing flow patterns in large estuaries, inlets, or where flow separation and 3-D flow
structures are thought to occur.
b. Obtaining velocity measurements near structures and in turbulent regions associated with
flow separation at solid boundaries.
c. Quantifying flow conditions in idealized cases for use in validating numerical modeling
techniques.
d. Quickly examining project impacts due to structure modification, addition, removal, or
relocation.
e. Observing the extent of flow three-dimensionality in order to determine the correct
numerical modeling approach.
As with all coastal engineering tools, there are advantages and disadvantages related to the precision
flow table.
Advantages:
a. Flow conditions can be controlled precisely.
b. The laser Doppler velocimeter provides precise, nonintrusive measurements of turbulent
velocity.
c. The small size of the table allows rapid (and inexpensive) changing of solid boundaries so
numerous experiments can be conducted over a short time period.
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