Fluid Dynamics Phenomena Induced by Air Permeability of Ski Jumping Suit Fabric

Abstract

Ski jumping is a sport in which the competitor is judged based on the flight form and flight distance; therefore, ski jumpers attempt to fly as far as possible upon take-off. The fabric used for ski jumping suits plays a crucial role in achieving favorable aerodynamic characteristics. It is generally assumed that ski jumping suits made from fabrics with low air permeability will have favorable aerodynamic characteristics. However, the effect of the air permeability of ski jumping suits on aerodynamic characteristics has not been completely clarified yet. The purpose of this study is to investigate the effect of air permeability on the aerodynamic characteristics of ski jumping suits. Wind tunnel experiments were carried out on the NACA airfoil clothed with ski jumping suit fabrics of different air permeability. The stall delay occurs and drag force decreases with an increase in air permeability. It was confirmed that the stall characteristics are greatly affected by the air permeability.