Relationship between Air Permeability and Aerodynamic Characteristics of Ski Jumping Suit Fabric

Abstract

In ski jumping competition, there are many regulations to ensure fairness. In the international ski jumping competition rules, 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 completely clarified yet. The purpose of this study is to investigate the effect of air permeability of suit fabric on aerodynamic characteristics. The fabrics with different air permeability are used and the wind tunnel experiments were carried out using the fabric clothed elliptic cylinder. The experimental results show that the stall characteristics are greatly affected by the air permeability. Furthermore, the flow around the fabric-clothed elliptic cylinder also varies, depending on the position of the fabric's air permeability on the upper surface of the elliptic cylinder. It is presumed that the aerodynamic performance of ski jumpers during a flight can be improved by adjusting the air permeability of the suit fabric.