Page 71 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

Tidal Energy Chapter | 3 63

TABLE 3.2 Type of Tide, Based on Form Factor
F (Eq. 3.20)
F Type of Tide
0–0.25 Semidiurnal form
0.25–1.50 Mixed, mainly semidiurnal
1.50–3.00 Mixed, mainly diurnal
>3.0 Diurnal form

FIG. 3.16 Form factor F, showing global distribution of semidiurnal (F < 0.25) and diurnal
(F > 3) tides.

tides [6]. For instance, as described in Section 3.9, the combination of semid-
iurnal M2 and S2 tidal constituents results in the spring-neap cycle, with a
frequency of
1 1 1
ω S2 − ω M2 = − = (3.21)
12 h 12.42 h 14.79 days
As tides propagate onto the continental shelves and into shallow coastal
waters, nonlinear forces and processes become significant. These forces include