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Unformatted text preview: AAE 334 Fall 2011 Mid-term #1 NAME:__SOLUTIONS_______________ One original hand-written formula sheet permitted. Calculator permitted. Phones, IPods, etc. turned off. Do your own work. Present neat and organized work leading to the correct answer for full credit. 1. [15 points] An airfoil in a flow of air with freestream velocity of 57 feet per second, pressure of 10psi and density of 0.0015 slugs per cubic foot has a pressure of 7.2 psi measured at one point on the airfoil. What is the value of the pressure coefficient at that point? Pressure coefficient is q p p c p , where 2 2 1 V q . Compute dynamic pressure first, remembering to convert from pounds per square foot to pounds per square inch. 2 1 2 1 2 1 2 2 2 3 2 436 . 2 436 . 2 57 0015 . 5 . 2 1 s ft s ft lb s ft slugs s ft ft slugs V q psi ft in ft lb ft lb q 0169 . 12 436 . 2 436 . 2 2 1 2 2 Now compute pressure coefficient: psi psi psi q p p c p 0169 ....
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- Fall '09
- Aerodynamics, Airfoil, Trailing edge, pressure coefficient, lb ft, surface air velocities