Airplanes create vortices in the air while flying due to the difference in pressure between the upper and lower parts of their wings, thus creating lift that keeps the airplane in the air.
When an airplane flies, its wings separate the air into two flows: one above and one below. The particular shape of the wing causes the air above to speed up, creating a low-pressure area, while below, the pressure remains higher. This difference in pressure causes the air to want to flow around the tips of the wings, creating areas of high turbulence at the ends, giving rise to vortices known as tip vortices. As these two air flows naturally seek to return to equilibrium, they begin to rotate around each other: this is how the visible vortices appear behind certain airplanes in flight (sometimes even visible under certain weather conditions like humid or misty weather). The greater the pressure difference between the top and the bottom, the more pronounced these vortices become. This is particularly true when an airplane flies slowly, with the wings highly inclined (in takeoff or landing configuration).
When an airplane flies, its wings automatically generate vortices, especially at the tips. Where does this come from? Essentially, above the wing, the air moves faster and the pressure is lower. Below, it's the opposite: slower air and higher pressure. At the tips of the wings, this creates a desire for the air beneath the wing to "escape" to the area above, creating a swirling motion: there you have your famous tip vortices.
These vortices are not just there for looks — they are directly linked to lift, in other words, the force that allows your airplane to stay in the air. By releasing energy into these vortices, the wing generates an upward reaction: this is exactly what supports the airplane. There's no way to completely avoid these swirling motions without sacrificing the ability to lift the aircraft. So, even though they cost a bit of energy, these vortices are actually the inevitable and necessary trace of the lift phenomenon.
At the tips of an airplane's wings, the pressure difference between the intrados (the underside of the wing, high pressure) and the extrados (the upper side of the wing, lower pressure) naturally generates tip vortices. These vortices, swirling at the wing tips, create turbulence that pulls air down behind the aircraft. As a result, the airplane must constantly produce extra force to compensate for this downward airflow. This necessary force causes what is known as induced drag, a detrimental aerodynamic resistance that forces the airplane to consume more fuel. The stronger the tip vortices, the greater the induced drag, thus reducing the overall efficiency of the flight.
The air vortices left behind by an airplane are what we call wake vortices, and to be honest, they can be quite problematic. These vortices, particularly violent behind large aircraft, take some time to dissipate in the air. A small plane flying too close behind a large aircraft can get caught in these swirling currents, risking a sudden loss of balance and control—which is not really ideal during landing or takeoff. These dangerous turbulence issues therefore require airplanes to maintain safe distances from each other in the sky and during sensitive phases. To make life easier for pilots, air traffic controllers take these separations very seriously, regularly adjusting the spacing between flights according to the size of the aircraft involved. Some airports even use special instruments to detect these disturbances and inform pilots in real-time of potential risks.
To reduce these annoying vortices, aerospace engineers often rely on adding winglets at the tips of the wings. These small winglets angled upward, mainly visible on newer aircraft, partially prevent the pressurized air beneath the wing from rising into the less dense air above. This significantly reduces induced drag, leading to less wasted fuel and fewer turbulence. There are also operational strategies, such as slightly increasing the spacing between aircraft during landing and takeoff phases, allowing these vortices time to dissipate naturally before the next aircraft passes. Another solution sometimes used is to adopt wings with specially designed profiles to better distribute pressure, thus limiting the creation of strong turbulent flows. These combined techniques make flights both more economical, more comfortable, and safer.
The formation of air vortices is directly related to the specific design of the wings, particularly their curved shape, which accelerates the air above the wing and slows it down below, thereby creating a pressure difference essential for lift.
To mitigate marginal vortices, some aircraft are equipped with vertical fins known as winglets or sharklets. These devices effectively reduce drag, allowing for fuel savings.
Migratory birds, just like cyclists in a peloton, use the same principle of air vortices to fly more efficiently, reducing their fatigue and saving energy over long distances.
The wake turbulence left behind by a large aircraft can persist for several minutes after it has passed. That is why aircraft typically maintain a minimum distance between each other to ensure safety.
Marginal vortices can pose a danger as they generate turbulence, also known as "wake turbulence," which can destabilize another aircraft flying nearby or just behind the first one. This explains why regulatory spacing is imposed between airplanes during landing or takeoff.
The air vortices created by airplanes are often invisible, but they sometimes become visible through moisture condensation, especially in high humidity or cool temperatures. This results in swirling white trails appearing at the tips of the wings.
Several devices exist to reduce the intensity of vortex shedding: winglets (curved wing tips pointing upwards), elliptical wings, and the optimization of wing geometry. These elements not only help reduce wake turbulence but also lead to significant fuel savings by decreasing induced drag.
Indeed, a wing with a large span generally reduces the intensity of the vortices formed at the wingtips. By increasing the span, the pressure difference between the upper and lower surfaces of the wing is distributed over a larger area, which decreases the strength of the vortices created.
Yes, all flying devices generate aerodynamic vortices, but their size and intensity vary depending on factors such as weight, wing shape, and the speed of the aircraft. The heavier and slower an airplane is, the more powerful the generated wake vortices generally are.
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