The effect is named after Heinrich Gustav Magnus. And who was this man? Well, he was a German physicist who discovered it in 1853, although Isaac Newton had previously observed and theorised about it centuries earlier.
However, Magnus’s contribution was not merely its discovery but also providing a detailed explanation of how the rotation of an object affects its path through a fluid—a concept that has been crucial in many areas of research and engineering.
The Magnus effect manifests when a spherical or cylindrical object spins as it moves through a fluid like air or water. The object’s rotation alters the fluid flow around it, creating an asymmetrical distribution of air speed around its surface.
This variation in fluid speed results in different pressures on the sides of the object, in turn generating a force perpendicular to the direction of movement. This behaviour is closely linked to Bernoulli’s principle, which explains how increases in fluid speed (in this case, air) lead to decreases in pressure.
As the cylinder rotates, for instance clockwise, it accelerates air on one side and slows it on the other, altering the streamline patterns and creating rotational flow.
This phenomenon modifies the air pressure around the cylinder, producing a force that can push the object towards the side of lower pressure. This effect is particularly noticeable in scenarios where the object’s angular speed and the air speed significantly interact.
Yes, this phenomenon has many applications. In sports, in power generation… and it also relates to aircraft! Some aircraft utilise the Magnus effect to generate propulsion. How do they do it? What kind of aircraft are capable? Let us explain.
In aviation, the Magnus effect is not just a theoretical study topic but has practical applications. A clear example is the cyclogyro, a type of aircraft that uses rotating rotors to generate lift, control, and propulsion because, as we know, planes can fly without engines.
Anton Flettner had the idea to use a horizontal cylinder in an aircraft, giving birth to the cyclogyro. Here, the aircraft’s propellers are rotating, capable of generating acceleration. However, the creation of this cyclogyro also faced issues like power loss and failures in the aircraft’s lift.
You can also see it in football. Have you ever seen a footballer kick in one direction and the ball goes the other way thanks to the Magnus effect? Well, it happens because of the Magnus effect.
This phenomenon is used by professionals to confuse the opponent, who does not know which way the ball is going, thanks to the effect the player can give it.
And not only in football, but also in other sports where balls are used, such as golf, baseball or tennis. And one of the sports that makes the most of it is undoubtedly billiards, where every shot is an opportunity to take advantage of the Magnus effect.
Yes, there are exceptions to the effect. And there are some places where it does not work, for example in space. Where? Well, in bodies without an atmosphere, such as our satellite, the Moon.
It also loses strength at high altitudes, far from sea level.
Isn’t it fascinating to see how principles like the Magnus effect, which might seem very complex or abstract, are applied in everyday things like football or planes?
Indeed, and just as with other phenomena like the Brocken spectre, nature offers us true wonders, and to help us understand them, there is science, providing an explanation for all of them.
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