| Tidal Forces |
Equilibrium theory makes the following assumptions:
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Tidal-potential can be determined from celestial mechanics
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Oceans of uniform depth cover the earth
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The earth is not rotating, so no Coriolis force acts
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No friction acts
Given these assumptions, equilibrium theory predicts a maximum tidal range of 0.5 - 1 m.
Dynamic theory takes the earth's true nature into account:
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Earth is rotating
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Continents exist
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Bathymetry is highly irregular
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Friction acts
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Tides are long waves (highest frequency harmonics are semi-diurnal) so they behave as shallow-water waves
The dynamic theory doesn't perfectly predict tides either, but it provides a much better explanation for observed tidal patterns. The most accurate method of tidal predication (near coasts, at least) is to carefully measure tides over an extended period, and use harmonic analysis. |
Equilibrium Theory of Tides