So on my way back to BU after Thanksgiving break, I was trying to sleep on the airplane when everything started to shake. This got me to thinking, what causes turbulence during flight?

In its basic form, turbulence is a disruption in the air flow over the wings of the plane (or bird). It can be caused by anything from a sudden drop in pressure around the airfoil, to a rapid change in wind or weather conditions, or even from an intersection with the disrupted air which forms as a wake behind an airplane.

Turbulent flow exists everywhere in our world. Natural fluid motion in all mediums, including water and air, experience turbulence in one form or another. Engineers are constantly faced with the challenge of overcoming turbulent flows, and even to utilize the turbulence to better design planes, flying objects, and even everyday objects which interact with Turbulent flows. For example, golf balls are designed with dimples to reduce the effect of turbulent flows and random motions in fluids. Airplanes are also specially designed to cope with the stresses and toils of turbulent airflow.

This effect of turbulent airflow is also seen as a plane or bird flies through the air, therein creating trailing vortexes. The edge of the wing slices through the air in such a way that air is pushed and spins. These vortexes are much, much stronger than any natural turbulent flow, and thus they create a much more volatile and concentrated disturbance in the air and in objects which cross the path of the vortex.

This video displays a simulation which demonstrates both turbulence’s effect on a flying object, as well as the effects of the generated vortexes created by planes in flight:

Wake Turbulence Simulation from Felipe Bachian on Vimeo.

Turbulence is a natural phenomena experienced in flight and through all mediums and fluids. While a minor inconvenience in everyday flight, turbulence provided a significant dilemma for flight to be engineered and evolved to cope with. Designers must factor in this effect of turbulent flow to provide improved “stability” and control in flight.


One Comment

Lorena Barba posted on December 13, 2011 at 6:22 pm

Richard Feynman once said that turbulence is the “most important unresolved problem of physics”. Wake turbulence, on the other hand, could well be the most important unresolved problem of general aviation! Airport operations are wholly dependent on avoiding wake turbulence.