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Converted document FLUTTER

FLUTTER

EXAMPLE 1
Problem
Write a computer program to solve the two-degree-of-freedom (pitch and plunge) problem using the p, k, and p − k methods, assuming Theodorsen unsteady aerodynamics for the k and p − k methods. For the Theodorsen aerodynamics, you should utilize the exact mathematical formulation for C(k).
Using this computer program, you should compute the flutter speed when a =  − 1 ⁄ 5, e =  − 1 ⁄ 10, μ = 20, r = 2 ⁄ 5, σ = 2 ⁄ 5.
Plot comparisons of the computed values of the damping and frequency as the reduced velocity changes.
Maple Code
Please refer to the Maple code link (Example 1).
EXAMPLE 2
Problem
Consider an incompressible, two-degree-of-freedom flutter problem in which a =  − 1 ⁄ 10, e =  − 1 ⁄ 15, μ = 25, r2 = 7 ⁄ 25, σ = 2 ⁄ 5. Compute the flutter speed and the flutter frequency using the classical flutter approach. For the aerodynamic coefficients, use first the approximation of
(1) C(k) = (0.01365 + 0.2808ik − (k2)/(2))/(0.01365 + 0.3455ik − k2).
Next, use the exact definition of the Theodorsen function, C(k). From an engineering viewpoint, discuss the differences in the results, in particular whether it is a good engineering approximation to use the approximate form of C(k). Plot the variation in the real and imaginary values of ωθ ⁄ ω and C(k) terms with k.
Maple Code
Please refer to the Maple code link (Example 2).