What is turbulence and what causes it on flights?
Turbulence experienced by aircraft can turn a smooth flight into a bumpy one – and even have dangerous consequences. And it is all caused by the movement of air in the atmosphere.
Airplanes achieve flight by taking advantage of Bernoulli's Principle, which states that air moving at a faster speed has a lower pressure than air moving at a slower speed.
A cross-section of an airplane wing reveals that the wing has a longer, curved top and a shorter, straighter bottom edge. As air the plane passes through splits the wing, the air riding on top of the wing has to travel a longer distance in the same amount of time as the air below the wing, and thus speeds up. This creates an area of high pressure under the wing, and an area of low pressure on top of the wing. Since things in nature move from high to low pressure, this creates lift on the wing, and causes the airplane to fly.
With calm background conditions, the lift over the airplane's wings is smooth and constant. But as the plane travels through areas of rising and sinking motion in the surrounding environment, the lift on the wings is interrupted or enhanced. This can cause the plane to lift or drop suddenly.
Trained pilots avoid flying through thunderstorms and other tall clouds whenever possible, as those clouds are a visual marker of areas of strong vertical motion and potentially dangerous turbulence.
Not all areas of rising and sinking air in the atmosphere are visible, however, and so-called "clear air turbulence" can be difficult to predict and detect, even as a plane approaches it.
While turbulence has led to documented injuries onboard airplanes, the airplanes themselves are designed to handle such extreme forces.