The aerodynamic drag force on a skier resulting from the viscosity of the air consists of two different types. If air flows in a perfect, streamlined, laminar flow around the skier’s body, the aerodynamic drag on the skier results from the shear velocity gradient at the surface and increases or decreases proportionally with the velocity of the airflow. Drag from laminar airflow is negligible in the context of this discussion. As the velocity of the airflow around the skier increases, however, the shear also increases until the laminar flow separates at some angle f on the downstream side of the skier’s body and turbulence develops in the wake that trails behind the skier. The momentum that transfers from the skier to the air in that turbulent wake represents a drag force on the skier.
KeywordsReynolds Number Wind Tunnel Drag Force Aerodynamic Drag Turbulent Wake
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- 2.The discussion of aerodynamic drag that follows is indebted to C. B. Mil-likan’s analysis of aerodynamics, Aerodynamics of the Airplane (Wiley, New York, 1941); for the parts of the discussion more specifically centered on skiing, we are indebted to S. C. Colbeck’s “An Error Analysis of the Techniques Used In the Measurement of High-Speed Friction on Snow,” Ann. Glaciol. 19, 19 (1994), and M. S. Holden’s “The Aerodynamics of Skiing,” Sci. Am. 258 (2), T4 (1988).Google Scholar
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