8 Summary and Conclusions
The U.S. Army Engineer District, Alaska, funded studies involving the new
CHL Precision Flow Table. The studies provided insight into the complex flow
regime of upper Cook Inlet, and the small-scale models of Cook Inlet illustrated
the probable shoaling mechanism at the Port of Anchorage. In addition, generic
flow table studies of flow separation and large-scale turbulence generation
examined potential scale effects that may occur in geometrically distorted
physical models. Results from the scale effects experiment will factor into any
decisions to construct a large physical model of Cook Inlet.
Summary of Study Tasks
The five tasks undertaken for this study are summarized in the following
paragraphs.
Task 1: Large-area idealized flow model of Cook Inlet
This model covered a larger region of Cook Inlet than the small-area model,
and the bathymetry was idealized with two horizontal surfaces at elevations
corresponding to 0 ft and -60 ft mllw. The objective of the model was to identify
and examine in a semiquantitative way the large-scale flow patterns in upper
Cook Inlet during maximum ebb and flood tide.
The large-area idealized physical model of Cook Inlet proved to be valuable
in understanding the complex flow patterns in the vicinity of Anchorage, AK.
Even though the model was very small, constructed at a highly distorted
geometric scale, and represented fairly complex bathymetry by simple horizontal
terraces, it still produced large-scale turbulent flow features known to exist in
upper Cook Inlet. Furthermore, the location and areal extent of the gyres and
eddies were qualitatively the same as in the prototype as confirmed by Alaska
District engineers.
Task 2: Small-area idealized flow model of Cook Inlet
This model was similar to the large-area idealized model, but it covered a
smaller area in the vicinity of the Port of Anchorage. In addition, bathymetry
was idealized using three terraces rather than two. The objective of the small-
area model was to study in greater detail flow patterns identified in the large-area
model in terms of potential contribution to sedimentation at the Port of
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Chapter 8 Summary and Conclusions
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