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    Aerodynamics

    • Two effective forces
        • Pressure
        • Friction

    Normal pressure and friction forces

    • For cyclists, pressure effect is much larger than friction due to non-streamlined body.

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    Attached and separated flow around a cylinder

    • Streamlined bodies incorporate gradual tapering to minimize pressure effect and separation of flui

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    Attached flow and pressure recovery along a streamlined body

    • 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 = 32.174 lbm-ft/lbf-s2
    • Drag
      • The force in the direction of relative flow.
    • Propulsion power to overcome drag:
      • Ŵ = drag force x relative vehicle velocity

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    Drag coefficients of various geometries

    • Laminar Flow
      • Layers of fluid flow slide smoothly over one another
    • Turbulent Flow
      • Boundary layer is composed of vortices that increase surface friction
      • Common at rear end of non-streamlined vehicle
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