Heat-Treatment Process Effects on Sprintwear Fabric Aerodynamics

Introduction: Heat-treatment temperature and surface configuration are primarily manufacturing-process variables, but they may also function as aerodynamic design factors for sportswear, a possibility that remains largely unexplored for sprintwear fabrics.

Methods: This study compared the aerodynamic drag of six fabric specimens—an untreated fabric and five heat-treated variants at 140°C single-side, 140°C double-side, 160°C single-side, 180°C single-side, and 200°C single-side conditions—using two simplified wind-tunnel models, a cylinder model and an airfoil-type model, at flow velocities of 7–11 m/s.

Results: The aerodynamic effect of heat treatment depended strongly on model geometry. On the airfoil-type model, several heat-treated fabrics exhibited lower drag coefficients than the untreated fabric, with the 180°C single-side treatment showing the largest reduction, approximately 20.4% at 9 m/s, while the 160°C single-side treatment showed consistently low drag at 10–11 m/s, with reductions of approximately 15.1%. On the cylinder model, differences among specimens were considerably smaller, with most values remaining within approximately ±3% of the untreated fabric. No single heat-treatment condition produced the lowest drag coefficient across all velocities and model geometries; rather, the optimal condition varied with both flow speed and surface curvature.

Conclusions: The 160°C and 180°C single-side treatments consistently ranked among the lowest-drag specimens on the airfoil-type model and emerged as the most promising candidates for further investigation into heat-treatment-based aerodynamic optimization of sprintwear fabrics.