Abstract
Ski jumping competition is a sport that competes at the total point of "Distance Point" that digitizes the flight distance and "Judges Point" that digitizes the beauty of flight attitude and landing, and ski jumpers attempt to fly as far as possible. In competition, many provisions for fairness are established. In the rules for ski jumping competition, suit fabric must show the air permeability of a minimum of 40 liters per m2/sec under 10 mm water pressure. However, the effect of air permeability of suit fabric on aerodynamic characteristics has not been fully clarified yet. The purpose of this study is to investigate the effect of air permeability of suit fabric on aerodynamic characteristics. Four types of fabric with different air permeability are used and the wind tunnel experiments were carried out using the fabric clothed elliptic cylinder. The maximum lift coefficient indicates the highest value for no air permeability case among the all cases. The drag coefficient decreases with increasing the air permeability. Also, the stall delay occurs for the fabric with high air permeability, and the lift to drag ratio at the high angle of attack can be improved. By increasing the air permeability, it was found that the flow enters the inside of the fabric, and it flows out from the surface of the fabric, thereby causing a difference in the stall characteristics.
