2. Aerodynamics

Boundary Layers — Quiz

Test your understanding of boundary layers with 5 practice questions.

Practice Questions

Question 1

Which integral expression correctly defines the momentum thickness θ of a boundary layer?

Question 2

Which region within a turbulent boundary layer is characterized by a linear velocity profile and dominant viscous shear?

Question 3

A flat plate has a trip strip height $k=0.05\,$mm, free-stream velocity $U=30\,$m/s and kinematic viscosity $\nu=1.5\times10^{-5}\,$m^2/s. Calculate the roughness Reynolds number $Re_k=Uk/\nu$ and determine if it exceeds the typical transition threshold of 600. Show your calculation.

Question 4

Which pressure gradient condition is most effective at delaying flow separation on an airfoil?

Question 5

In a laminar boundary layer on a flat plate with $U_\infty=10\,$m/s and kinematic viscosity $\nu=1.0\times10^{-5}\,$m^2/s, estimate the boundary layer thickness $\delta$ at $x=1\,$m using the Blasius solution $\delta\approx5.0\,x/\sqrt{Re_x}$. Show your calculation.