Turbulence: One of the Great Mysteries of Physics

Sometimes, when we board a plane, the fuselage suddenly feels vibrate whereas when seen outside the window there is nothing. This vibration is even worse when the plane enters the cloud. This is called turbulence.

Turbulence in the vortex at the wing tips of the aircraft.

What Exactly Is Turbulence?

So far, after decades of research, in fact, we know very little about turbulence. Simply stated, turbulence is a change in pressure and flow velocity that becomes chaotic.

Turbulence occurs in all moving fluids. The fluid itself is a substance that can flow like liquid, gas, and plasma. Because it occurs in all fluids, turbulence can occur in streams, ocean currents, winds, stirred coffee, smoke that moves upward, including airflow on the plane that causes the fuselage to vibrate.

How Far Do We Know About Turbulence?

Fluid flow usually has two types of flow, namely Laminar Flow and Turbulence Flow. Laminar flow is a stable and smooth flow. Whereas turbulence flow, as explained before, is irregular.

Copyright: energy2d, Source

In the illustration above we can clearly see the difference between laminar flow and turbulence flow. If we pay attention, when the turbulence flow is farther away from the box, the flow will be more chaotic. The same thing happens with smoke. A simple example is when you light a stick and then wait for the fire to die. Even in quiet conditions, the smoke which is initially under calm is getting more and more haughty.


Turbulence itself has several characteristics.

1. Turbulence is always chaotic

Chaos is different from Random. Chaos depends on the initial conditions while random does not. It is very difficult to predict the end result of chaos even though we have a lot of information about it.

Small input differences become large output differences.
Source

In the animation above, even very small input differences can make pendulum motion very different going forward.

2. Turbulence also occurs at different scales

Turbulence occurs from a large scale, such as the Earth’s climate, while it is like the movement of wind through skyscrapers, to a small scale like in a glass of coffee.

Turbulence at the climate level.
Copyright: NASA/NOAA GOES Project Dennis Chesters

Why Is Understanding Turbulence Important?

Fluid that flows occurs almost everywhere. That way if we can understand turbulence, of course it’s very influential in various fields and aspects of life. Like being able to design windmills more efficiently, be able to predict the weather better, or even be able to manipulate tornado winds. In addition, in the industrial world, flow pipes can be better designed which will greatly save energy and costs.

Conclusion

Turbulence is chaos that occurs in fluid that flows / moves and this happens almost everywhere. So far this turbulence phenomenon itself still has a lot to be studied and studied. Because turbulence is chaotic, predicting and understanding it is indeed quite difficult. However, if this understanding is successfully obtained, there will be a significant development in human life.

Resources and references:

  1. Turbulence: one of the great unsolved mysteries of physics – Tom├ís Chor – TED-Ed
  2. The Internet Is Obsessing Over This ‘Impossible’ Water Stream – Science Alert
  3. Laminar and turbulent flows – energy2d
  4. Chaos theory and how to predict the future – Square Holes
  5. A New View: NASA/NOAA Water Vapor Animations Over Oceans – Nasa

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