This paper describes the behavior of wake-flow field behind a soccer ball measured in a wind tunnel with no or low spin based on the aerodynamic force data acting on the soccer ball. The experiment was performed through visualization of the wake-flow field, the aerodynamic force measurement, the applications of tuft grid method and PIV. The tuft measurement and the force coefficient Cs measurement were synchronized at the ball speed of 26 m/sec. It was found that in the wake, two vortexes were shed and they rotated around the ball center axis in rather random manner and then, the two vortexes were merged to disappear near the center axis. This procedure was repeated. From the PIV measurement result, it was recognized that the size of wake-flow field becomes small for the wind velocity Reynolds number larger than the critical value.
