Magnus effect applied to football

Have you ever wondered how footballers do the famous curved shot?

In these days of great emotions for the 2021 European football championships, our FEM/CFD Analysis and Calculation team asked this question, finding the scientific motivation that governs the famous “curved shot”, creating this simulation using the ANSYS Fluent software, combining the overset mesh technique with the 6dof model to create the ball.
We’re talking about the Magnus effect.

The Magnus effect in fluid dynamics is a physical effect that can be explained through Bernoulli’s theorem which concerns the motion of bodies in the air and which, given a certain initial rotation, induces the bodies to deviate from a parabolic trajectory following a particular curve.
Think of shots: have you ever seen a goal scored directly from a corner? The ball flies away from the baseline and then returns to the far post. How does the ball turn like this?

First of all, it should be noted that to apply the Magnus effect to the ball it should first be spinning. If there is no spin, the ball will perform a simple parabolic motion, proceeding along a trajectory that follows a straight line in its horizontal component.

If a spin is put on the ball, an additional force takes over other than the force of gravity, which is responsible for deflecting the balloon in the air. What is normally called “Effect” (or in this European Championship, “curved shot”).

Let’s better explain the Magnus effect
Due to the forces of viscous friction between the air and the ball, the latter drags the surrounding air with it: the air thus flows differently between the two sides of the ball. If the ball did not spin, the air would flow with the same speed on both sides, but since the ball spins on one side, the air will flow more slowly than the other, on which it will flow faster.
According to Bernoulli’s Theorem, we know that the higher the velocity, the lower the pressure. A pressure difference is therefore created and consequently a lateral thrust force, adding a horizontal component to the movement of the ball.

Let’s better explain the Magnus effect

Due to the forces of viscous friction between the air and the ball, the latter drags the surrounding air with it: the air thus flows differently between the two sides of the ball. If the ball did not spin, the air would flow with the same speed on both sides, but since the ball spins on one side, the air will flow more slowly than the other, on which it will flow faster.
According to Bernoulli’s Theorem, we know that the higher the velocity, the lower the pressure. A pressure difference is therefore created and consequently a lateral thrust force, adding a horizontal component to the movement of the ball.