Question

Which of the following is not correct for symmetric airfoil according to the fundamental equation of thin airfoil in transformed coordinates?

(a) 0≤θ≤π

(b) \(\frac {dz}{dx}\)=0

(c) ξ=\(\frac {c}{2}\)(1-cosθ)

(d) γ(θ)=0

I had been asked this question in unit test.

My doubt stems from The Symmetric Airfoil topic in chapter Incompressible Flow over Airfoils of Aerodynamics

Answer 1

The correct option is (d) γ(θ)=0

Best explanation: The transformation for thin airfoil theory uses ξ=\(\frac {c}{2}\)(1-cosθ) to make the coordinate transformation, where 0≤θ≤π. For a symmetrical airfoil (\(\frac {dz}{dx}\)=0), while γ(θ)=0 is not true for all values of θ.