單車空氣動力學(xué)aerodynamicsofcycling(編輯修改稿)
2025-05-28 22:23 本頁面
【文章內(nèi)容簡介】 from Bicycle Science pg. 174 Aerodynamics ? Drag Coefficient ? CD = drag/(area x dynamic pressure) ? Dynamic Pressure can be approximated for speeds under 100 mi/h as: ? Dynamic pressure = ρV2/2gc ? gc = lbmft/lbfs2 ? Drag ? The force in the direction of relative flow. ? Propulsion power to overe drag: ? ? = drag force x relative vehicle velocity Aerodynamics Drag coefficients of various geometries Figure from Bicycling Science pg. 191 Aerodynamics ? Laminar Flow ? Layers of fluid flow slide smoothly over one another ? Turbulent Flow ? Boundary layer is posed of vortices that increase surface friction. ? Common at rear end of nonstreamlined vehicle Turbulent Laminar ry/ELEC/l2fig/ Bicycle Aerodynamics ? Bicycle is responsible for 2035% of drag. ? Loose Clothing increases drag by up to 30%. Bicycle Aerodynamics Position ? Positions ? Goals: reduce frontal area amp。 reduce drag coefficient CD Frontal Area CDA Power to Overe Drag Tops .55 m2 .632 m2 345 W Hoods .40 m2 .40 m2 220 W Drops .88 .36 m2 .32 m2 176 W Bicycle Aerodynami
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