ae ee Sere mir ne ee ee 
Even if the waves on the sea surface had infinitely long 
crests, the models studied in this chapter would be inadequate 
for very subtle reasons which will be discussed in the next chapter. 
For these reasons, equations (6.5) and equations (6.6) were only 
indicated in Plate XIV. Various approximate results based upon 
the assumption that the individual groups in the sum of wave 
groups do not overlap to the extent that the potential energy 
associated with one group is affected by the presence of the 
neighboring groups can be obtained. The difficulty in the analy- 
sis of equations (6.5) and (6.6) lies in the fact that it appears 
that the wave record cannot be expressed as the sum of a number 
of sine waves in a form which applies to the whole sea surface. 
Even the most general model described by 7) Ty 60209) could not 
be made to fit an actual observation of waves on the sea surfacee 
The methods of Fourier Integral theory have been pushed as far 
as practicable, and it becomes necessary to introduce new con- 
cepts in order to obtain more realistic models. 
4G 
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