Deon+-+Tidal+resonance

Back to FORCED OSCILLATION AND RESONANCE Tidal Resonance

__Terms:__ Resonance: In physics, this is when a system absorbs more energy during a period when the frequency of a driving oscillation on that system equals the system's natural frequency. Natural Frequency: The natural oscillating of a system Damping: The energy loss of a system when oscillating due to friction, either natural or artificially imposed

Tidal Resonance is an occurrence which results in some of the world's highest tides.

__How it works:__ When a large incidental tidal wave takes the same amount of time to travel from the mouth of a bay to the far shore and back is the same as the time between high and low tides. This means that the repeating wave can be reinforced by synchronizing with the lunar tides, and is therefore amplified (the driving frequency is the repeating wave). In this way, tides at sites like the Bay of Fundy, (which is famous for it's high tides), can differ by about 17 meters between high and low tide. On the right is a satellite image which shows the dramatic changes between high and low tide in the Bay of Fundy.

Tidal waves can also be reinforced by reflections between the coast and the continental shelf edge, which should be preferably a quarter of the wave length of a tidal wave wide (the shelf width). The reflections reinforce the wave and create much higher tidal range at the coast - When the incidental tidal wave is at a frequency that is resonant to the reflection waves, this draws energy from the waves in deeper ocean onto the shelf, creating tidal waves with higher amplitudes and therefore higher tides. This can also occur along the N.W. Australian continental shelf. This can be seen practically using the fact that tides along a coast behind a continental shelf go much higher than islands in the middle of the ocean.

Bibliography: [] @http://earthobservatory.nasa.gov/IOTD/view.php?id=6650 http://www.spiritus-temporis.com/tidal-resonance/see-also.html