Figures 8, 9 and 10 show results for domains having resolutions of 3, 6, 8 and 15
nodes per wavelength. The numerical solution in Figure 8 shows little correlation to the
lab data. The results in Figures 9 and 10 show a progression to the lab data as the
resolution increases. The linear solution in Figure 10 matches the data better than either
of the previous resolutions, however section 7 does not agree with the data in the region 6
to 10 meters behind the shoal. A grid resolution of about 10 or greater nodes per
wavelength is generally thought to be necessary for an accurate solution to most problems.
The non-linear dispersion mechanism was applied only to grids containing 15
nodes per wavelength. This mechanism was not run for lower resolution grids because the
linear amplitude solution is used in the formulation of the non-linear effect. Inclusion of
the non-linear dispersion relation in the calculations has a noticeable effect on the solution
for all sections (Figure 10). Sections 3 and 5 show a closer fit to the data in the areas to
the left and right of center. Section 7 shows the most marked improvement in the region
that begins 6 to 7 m behind the shoal.
This example problem showed that the results produced by the linear run of CGWAVE
are good, provided that a fine enough grid resolution is used.
The best results are
obtained with the highest grid resolution.
The addition of the non-linear dispersion
relation (wave-wave interactions) mode shows a substantial improvement in the model
estimates, yielding the best comparison to the measurements.
59-83.
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