Lift and Drag from Pressure Distribution over an Air Foil

AI Thread Summary
Calculating lift and drag from pressure distribution over an airfoil is complex, as it involves understanding both static and dynamic pressure. While lift and induced drag can be determined, skin friction or parasitic drag presents challenges due to its dependence on the boundary layer characteristics. The shear boundary layer can thicken and transition from laminar to turbulent flow, affecting the effective shape of the airfoil. Accurate pressure distribution measurement may require instrumentation that could impact airflow. Simplified models often rely on the Navier-Stokes equations to analyze these forces effectively.
Triggers12
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Pretty simple question:

Is it possible to completely calculate Lift and Drag from the pressure distribution over an airfoil?

Atm, I have Lift worked out as well as the Induced drag ( correct me if I'm wrong. ) but am having trouble working out how it would be possible to get the skin friction / parasitic drag.

Thanks for your help!
Trigs
 
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Triggers12 said:
Is it possible to completely calculate Lift and Drag from the pressure distribution over an airfoil?
How would you determine the pressure distribution over an airfoil? Perhaps some form of intrumentation, but that would have some effect on the flow. A simplified model could use static pressure distribuition and the normals (line perpendicular) to the sections of surface of a wing, but there are other factors. Static pressure isn't directional, but dynamic pressure and any related changes in momentum of the air are directional. Skin friction is nearly parallel to a wing surface. The shear boundary layer thickens over time, may detach and reattach as it transitions from laminar to turbulent, so that changes the effective air foil shape.

The best mathematical models for lift and drag are usually based on some simplified form of Navier Stokes equations:

http://en.wikipedia.org/wiki/Navier–Stokes_equations
 
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rcgldr said:
How would you determine the pressure distributaion over an airfoil? Perhaps some form of intrumentation, but that would have some effect on the flow. A simplified model could use static pressure distribuition and the normals (line perpendicular) to the sections of surface of a wing, but there are other factors. Static pressure isn't directional, but dynamic pressure and any related changes in momentum of the air are directional. Skin friction is nearly parallel to a wing surface. The shear boundary layer thickens over time, may detach and reattach as it transitions from laminar to turbulent, so that changes the effective air foil shape.

The best mathematical models for lift and drag are usually based on some simplified form of Navier Stokes equations:

http://en.wikipedia.org/wiki/Navier–Stokes_equations

Hey thanks for the response,

Trigs
 
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