Abstract
Aerodynamic characteristics of soccer balls, particularly drag crisis, changes with the change of the recent panel shape. The change of the flow around the ball brings the change of the aerodynamic characteristics. Various visualization measurement techniques were presented to grasp their characteristics. The change of drag characteristics showed that the boundary layer on each panel which constituted a ball, grew from laminar to turbulent by the oil film method. In addition, the carbon tetrachloride fume method in the wind tunnel experiment and by an ejector were introduced and their findings show that ball wake changed with Reynolds number and showed and the changes of the ball path were related to by smoke analysis in the latter. Furthermore, tuft variation were related to the side force. And also the change of the ball path was related to the low spin of the ball by high-speed video picture analysis.
