76
DETERMINISTIC DESCRIPTIONS OF OFFSHORE WAVES
Dean’s study of 1974 is a quantitative one, based on the closeness of fit of the
kinematic dynamic free surface boundary conditions. It is limited to waves lying
between the upper breaking limit curve and the lower curve labeled H — Hq/ I
in Figure 3.9. We see that within this range there are three possibilités: the
cnoidal first order, the linear, and the free stream function fifth order theory. If
it is desired to use only analytic théories, then the range of application of the
cnoidal theory may be extended to cover ail of that région lying below the lower
dashed curve; the Stokes fifth order may be employed for that région lying below
the upper dashed curve; and the linear theory may be extended for application
to the région lying between the two dashed curves.
8
d/T2 ft/sec2
0.01
o.l
10
Figure 3.9 Periodic wave théories providing best fit to dynamic free surface
boundary conditions. The région of validity for the free stream function fifth order
theory is encompassed by the bold boundary lines (Dean, 1974).
Le Mehaute’s study of 1976 appears to be based somewhat on subjective considérations, although it does cover the entire range of physically possible waves
of permanent form. Only the analytic théories are shown in Figure 3.10. Here,
L dénotés the wave length A. When the stream function fifth order is included,
DETERMINISTIC DESCRIPTIONS OF OFFSHORE WAVES
Dean’s study of 1974 is a quantitative one, based on the closeness of fit of the
kinematic dynamic free surface boundary conditions. It is limited to waves lying
between the upper breaking limit curve and the lower curve labeled H — Hq/ I
in Figure 3.9. We see that within this range there are three possibilités: the
cnoidal first order, the linear, and the free stream function fifth order theory. If
it is desired to use only analytic théories, then the range of application of the
cnoidal theory may be extended to cover ail of that région lying below the lower
dashed curve; the Stokes fifth order may be employed for that région lying below
the upper dashed curve; and the linear theory may be extended for application
to the région lying between the two dashed curves.
8
d/T2 ft/sec2
0.01
o.l
10
Figure 3.9 Periodic wave théories providing best fit to dynamic free surface
boundary conditions. The région of validity for the free stream function fifth order
theory is encompassed by the bold boundary lines (Dean, 1974).
Le Mehaute’s study of 1976 appears to be based somewhat on subjective considérations, although it does cover the entire range of physically possible waves
of permanent form. Only the analytic théories are shown in Figure 3.10. Here,
L dénotés the wave length A. When the stream function fifth order is included,