Sea Waves

The surface of the sea is calm if there is no wind for some time. as soon as the wind starts to blow, however, pressure is created on the surface molecules of the sea creating waves whose height increases according to the increase of wind pressure. The movement of the waves is in the direction of the wind, but at a lower speed. As the wind dies down or ceases to blow, the wave movement continues for some time at great distances and is called ondulation. The main elements of waves Waves are made up of the following main elements: - speed 'V' with which the crest of wave moves (measured in knots) - length 'L' is the horizontal distance between two crests (measured in feet) - time 'T' is the time between two consecutive crests (measured in seconds) - height 'H', is the vertical distance between the peak and the base of the wave (measured in feet) The speed, length and time are linked together as follows: V = 3.1 T L = 5.1 T2 In practice the surface of the sea is not level because the waves are of different length and height. There are therefore no series of simple waves. The height and length of a wave depend on the depth of the sea, the speed of the wind, the surface below and for how long. In the ocean, the kinetic and potential energy of a series of waves is analogous to L.H2. For waves of 25 feet, for example, this would be expressed in the form of energy transferred per foot of beach equal to 230HP. This explains the destructive force of the sea on coastlines, harbours and marine constructions. When the waves form a foam on their crest they are losing energy.