A commercial airplane is flying at an altitude of 8 km. The mean aerodynamic chord length of its wing is 8 m. If the wall shear stress (τw) and momentum thickness (θ) in terms of boundary layer thickness (δ) at the half-chord length is approximated by:
tw(x) = 0,0225 pU²(v/Uδ(x))¹/⁴
assume that cf = 2dθ/dx and θ(x) = 7/72δ(x)
Where U is the freestream velocity
ν is kinematic viscosity of air at 8 km
rho is density of air at 8 km
Boundary layer thickness (δ) at the half-chord length is 4.8 cm.
(You need to derive boundary layer thickness equation at first)
Calculate the Mach number and Mach angle.
