Question

For a Reynolds number Rec=10×10^5 and chord length 1m, what is the turbulent boundary layer thickness at the trailing edge (in cm)?

(a) 0.0216

(b) 0.037

(c) 2.16

(d) 0.37

I got this question in quiz.

My enquiry is from Turbulent Flow in chapter Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Correct answer is (c) 2.16

Easy explanation: The turbulent boundary layer thickness is given by δ=\(\frac {0.37x}{\sqrt[5]{Re_c}}\) where in our question x is the chord length. Solving this we get the thickness to be 2.16 cm or 0.0216m. Note that the answer is not 0.0216 since that is wrong in the required units.