CHAPTER 6
CONCLUSIONS AND RECOMMENDATIONS FOR FURTHER STUDY
A numerical solution for the circulation and waves in coastal regions has been presented.
The solution method uses an alternating direction implicit method of solving the depth
integrated equations of momentum and continuity. Wave forcing terms are obtained through
a parabolic approximation to the linear mild slope equation for wave propagation over
varying depths and currents. The numerical solution involves an iteration between the
parabolic wave solution and the ADI circulation solution.
The model was run for several test cases. These include cases with varying topogra
phy, such as rip channels and bar gaps. The model was also tested with shore parallel and
shore perpendicular breakwaters represented as infinitesimally thin impermeable barriers.
Comparisons were made with analytical and experimental results. These comparisons were
favorable. In particular comparison of the results from the model in simulating the experi
ments of Gourlay (1974) show the predictive capability of the model. The model was also
run for an idealized shore parallel breakwater varying the aspect ratio of the length of the
breakwater to the distance offshore of the breakwater to determine the relative importance
of this parameter.
The primary conclusion of this study is that it is possible to get good predictive re
sults using a numerical model that incorporates some simplifications of the physical reality.
In the present study the three-dimensional flows that are encountered in nature are rep
resented by two-dimensional depth averaged velocities. Simplifying assumptions are also
made concerning bottom friction, momentum transfer or mixing, wave breaking and wave
energy dissipation. For each of these topics it is possible to argue that nature is greatly dif
ferent and more complex than the assumptions embodied in this report. Yet the results (in
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