It seems to be a banal question, but there are some interesting nuances.
Waves arise for various reasons: due to the wind, the passage of a ship, an object falling into the water, the attraction of the moon, an earthquake, an underwater volcanic eruption, or a landslide. But if from a passing vessel or falling of an object they are caused by the displacement of liquid, the attraction of the Moon and the Sun contributes to the appearance of tidal waves, and an earthquake can cause a tsunami, with the wind more difficult.
This is how it happens …
This is about the movement of air - there are chaotic vortices in it, small at the surface and large in the distance. When they pass over the reservoir, the pressure decreases, and a bulge forms on its surface. The wind begins to press harder on its windward slope, which leads to a pressure difference, and because of it, the air movement begins to "pump" energy into the wave. In this case, the speed of the wave is proportional to its length, that is, the longer the length, the greater the speed. The height of the wave and its length are related. Therefore, when the wind accelerates the wave, its speed increases, therefore, the length and height increase. True, the closer the wave speed is to the wind speed, the less energy the wind can give to the wave. If their speeds are equal, the wind does not transfer energy to the wave at all.
Now let's see how waves are generally formed. Two physical mechanisms are responsible for their formation: the force of gravity and the force of surface tension. When part of the water rises, the force of gravity tries to bring it back, and when it falls, it displaces neighboring particles, which also try to return. The force of surface tension does not care in which direction the surface of the liquid is bent, it acts in any case. As a result, water particles oscillate like a pendulum. Neighboring areas are "infected" from them, and a surface traveling wave arises.
Wave energy is well transferred only in the direction in which the particles can move freely. It is easier to do this on the surface than at depth. This is because the air does not create any restrictions, while at depth, water particles are in very cramped conditions. The reason is poor compressibility. Because of it, waves can travel long distances along the surface, but very quickly fade deeper.
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It is important that during the wave the particles of the liquid hardly move. At great depths, the trajectory of their movement has the shape of a circle, at small depths - an elongated horizontal ellipse. Thanks to this, ships in the harbor, birds or pieces of wood swing on the waves without actually moving on the surface.
A special type of surface waves are the so-called rogue waves - giant single waves. Why they arise is still unknown. They are rare in nature and cannot be modeled in a laboratory setting. Nevertheless, most scientists believe that rogue waves are formed due to a sharp decrease in pressure above the surface of the sea or ocean. But a more thorough study of them is ahead.
Yulia Skopich