This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: AOE 3104 Aircraft Performance Exam #1 Solutions Problem 1. (30 points) An airfoil is being tested in a wind tunnel at standard sea level conditions. The free stream flow velocity is 160 ft/s. The pressure coefficient at a particular point on the airfoil is C p = . 60. What is the flow speed at that point? If the wind tunnel speed is increased to 700 ft/s, what is the new pressure coefficient at the test point? What is the Mach number at the test point? Solution. Standard sea level conditions are ρ ∞ = 2 . 377 × 10 − 3 sl / ft 3 , T ∞ = 518 . 69 ◦ R , and P ∞ = 2116 . 2 lb / ft 3 . The speed of sound in standard sea level conditions is a = radicalbig γRT = radicalbig (1 . 4)(1716 . 488 ft lb / sl ◦ R)(518 . 69 ◦ R) = 1116 . 4 ft / s The free stream Mach numbers is therefore M ∞ = 160 ft / s 1116 . 4 ft / s = 0 . 143 < . 3 The flow may be treated as incompressible. Using Bernoulli’s equation for incompressible flow (and ignoring the small contribution from gravity), we have...
View
Full
Document
This document was uploaded on 02/05/2012.
 Fall '09

Click to edit the document details