Testing
Methods for Testing the Soccer Balls
Wind Tunnel (static test)
Wind tunnel testing is one of the most common ways for
simulating the flight path of the ball. Wind tunnel creates
the aerodynamic forces on the ball and lets us observe the
way the ball acts with the forces applying on it.
The balls are placed in the wind tunnel and connected to a
force balance with a support. Test can determine the air
drag on the ball. Usually the test is performed with
multiple different wind speeds to see the variation in
results at different speeds as the ball is kicked with
different force which also varies the speed the ball is
flying with during the game.
Plot of Re number vs. drag [N] from "Aerodynamics of modern soccer balls" by Luca Oggiano, Lars Saetran.
- Force balance is a balance capable of measuring multiple
forces and momentums around all three axes.
Image of a ball in wind tunnel from "Aerodynamics of contemporary FIFA soccer balls" by Alam, Firoz, et al.
Spinning Test
The lower the Re number for the ball the higher the side
force acting on the ball.
Plot showing the
spinning parameter against the side force coefficient
from "Aerodynamics of
modern soccer balls" by Luca Oggiano, Lars Saetran.
Plot showing the Cs-Sp
curves for different Re values from "Aerodynamics of modern soccer balls" by
Luca Oggiano, Lars Saetran.
Simulation
A numerical simulation estimates the trajectory of balls if
kicked with the same initial conditions. Using equations of
motion using the given initial conditions, where mass,
radius, area and gravitational acceleration are constant.
Simulation is usually done after the wind tunnel tests, so
the results can be used for simulation.
Plot of the used
angles from wind tunnel test results from "Aerodynamics
of modern soccer balls" by Luca Oggiano, Lars Saetran
Plot showing different trajectories of the tested balls from "Aerodynamics of modern soccer balls" by Luca Oggiano, Lars Saetran.