抄録
The mechanism of less spinning soccer ball has been analyzed by the wind tunnel experiment. Used at the large wind tunnel to observe the two longitudinal vortices behind a soccer ball. These two vortices are equivalent to the tip vortex of the aircraft. FIFA World cup South Africa matches were held at 1500m altitude where air density is low. The displacements are calculated with tunnel wind experimental data, compared the distance of the soccer ball flight distance by a difference of the air density of the sea level 0m and 1,500m. The soccer ball flights by 1 meter long in the X direction.
