December 8, 2022

Wave formation mechanics

At the sight of waves in the ocean, people’s hearts stop, and it seems that this is some magic. But physics is behind the magic. Moreover, it is not so difficult

What is swell?

In the context of the ocean, sea, or lake, a Swell is a series of mechanical waves on the surface of the water that occurs in the absence of a direct, direct impact on it from the external environment, such as wind tremors, etc.

Such waves are formed due to current in regions significantly remote from the coast

The best waves for surfing result from the interaction of winds on the water’s surface far, far away in the ocean.

So the wind is the main factor in the formation of waves suitable for surfing.

“Everything is born where there is nothing.”

It all starts far out in the ocean, where strong winds blow and storms rage. The wind blows from an area of ​​high pressure to a low-pressure place.

These areas are separated by many kilometers in the sea, so the wind blows over a vast area, transferring part of its energy to the water due to the frictional force.

Where this happens, the ocean is more like a bubbling soup: like a storm at sea, only the scale is more significant.

There are small and large waves here, all interspersed, superimposed on each other. However, the energy of water also does not stand still but moves in a specific direction.

Because the ocean is very, very large, and waves of different sizes move at different speeds, during the time until all this seething porridge reaches the shore, it is “sifted,” some small waves add up to others into large ones, others, on the contrary, mutually destroyed.

Ocean Waves- Groundswell vs Wind swell
As a result, the GroundSwell comes to the shore – even ridges of waves, divided into sets from three to nine with small intervals of calm between them

A Swell is a series of mechanical waves on the surface of the water that takes place without the direct influence of the environment.

It is essential to understand that although we see waves moving, not water is moving, but energy.

Water molecules remain in place, making circular vibrational movements. Each molecule pushes the neighboring one, transfers power, and slightly changes its trajectory.

As a result, the molecule describes a circle but remains in place.

The local coastal wind can also form small waves, but it can also degrade the ocean’s quality; it all depends on its direction.

Wind swells are waves that do not have time to “sift” by distance since the storm is raging not so far from the coast

Wind swells are usually of inferior quality to ground swells, since large and small waves come in a mixture, however, and they can be rolled, thanks to surfing, for example, in Sochi.

If we talk about the effect of wind on the groundswell, if it blows on the shore (the so-called “onshore” from the English. Onshore), it is the culprit of rough and closing waves, while ), on the contrary, promotes the formation of a sound wave, since it works as a holding pillow.

How are waves formed?

Not every swell is destined to be the waves of surfing. Although, it would be more correct to say – not everywhere

For a lock to be caught, it must break in a certain way. Wave formation for surfing depends on the seabed structure in the coastal area.

The ocean is bottomless, so the mass of water moves evenly, but when the wave reaches shallow water near the coast, the lower molecules cling to the bottom and, firstly, slow down, and secondly, they are forced upward.

As a result, the wavelength is shortened, and the crest grows; the wave becomes higher.

The depth, or shallowness, reaches a critical value; the rising wave can no longer become larger and collapses.

It happens is called the line-up, and this is where surfers sit, waiting for a suitable lock

The waveform directly depends on the shape of the bottom: the sharper it becomes shallow, the stronger the wave.

Usually, the most brilliant and even trumpeting waves are born. The elevation change is almost instantaneous, for example, at the bottom of a huge rock or the beginning of a reef plateau.


The drop is gradual, the bottom is sandy, the waves are gentler and slower.


Thus, for the formation of sound waves for surfing, a combination of many factors is needed: for a storm to pass in the distance, a good swell blows in the right direction, so that this swell has no obstacles on its way, and the bottom near the coast has a particular shape.

It would seem physics, but as you imagine how much of everything should coincide, you immediately understand – magic.