Aerodynamics

• Two effective forces

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

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

• 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

• 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