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THE DEVASTATING
WAVE
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Thedevastating wave is a project of analysis on the wave motion of the sea, onkinetic energy and on the effects on the territory.
The wavesare irregular movements produced by the wind on the surface of the water andare felt at a depth of more than 200 meters.
Sciencetells us that the displacement of waves is due to vertical oscillations ofwater molecules and not to a horizontal displacement.
In fact, iffor example we place an object floating in the sea water, moved by the waves,the same undergoes vertical and not horizontal movements such as movingforward. Only the shape of the wave shifts laterally, that is, thetransformation of water due to the force of the wind.
Then, thewave raises the water particles and moves them further forward, so thatcircular oscillations occur around a point. Then, following the rotary motion,the same particles are lowered and moved back.
Near theshore the rotating motion of the particles becomes elliptical due to the modestdepth of the sea waters.
This is dueto friction with the seabed, which slows the speed of water particles.
The upperpart of the wave, however, does not slow down its speed by bending forward andforming the break.
The waterparticles move horizontally.
The water,then, spills on the shore and returns to the sea giving rise to the undertow.
How can wemeasure the strength of the sea?
There aremeasuring scales, the Douglas Scale and the Beaufort Scale:
• TheDouglas Scale measures the strength of the sea by determining the condition ofits state based on the average height of the waves.
• TheBeaufort Scale provides indications of wind strength.
DOUGLASSCALE:
The DouglasScale describes the state of the sea waves in 9 levels:
• Level 2is equivalent to a shallow sea where the wave height ranges from 0.10 to 0.50meters;
• Level 9is equivalent to a stormy sea where the height of the waves is over 14 meters.
There arealso two types of stairs:
• Live Sea(Wind Sea);
• Dead sea(Swell).
Live Sea(Wind Sea):
the wavemotion is generated directly by the wind.
Dead sea(Swell):
In thiscase there may be two wave effects:
• the wavemotion occurs as a consequence of storms that persist in other areas, thisphenomenon is called long waves;
• the wavemotion is the residue of a very strong wind, but that has stopped blowing. Thisphenomenon is called dead waves.
This typeof scale uses two measurement parameters, the height and length of the waves.
SCALABEAUFORT
Accordingto this scale, waves are generated by wind blowing on the surface of the sea,describing the intensity of the wind.
TheBeaufort Scale is divided into 13 levels of intensity:
• the thirdlevel, also called "light breeze", indicates the wind that blowsbetween 6 and 11 Kmh with waves about 20 cm high;
• thetwelfth level, called "Hurricane", indicates a wind speed higher than118 Kmh with waves exceeding 14 meters.
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