The polished wing of an unmanned aerial vehicle can be regarded approximately

as a flat plate with a total wing span of $15$m and a chord length $($length in the

streamwise direction$)$ of $0\mathrm{.}7$m$.$ The vehicle is flying at a constant velocity of

$30$m$.$s$-1$

$.$

$($i$)$ Calculate the total skin friction drag force on both surfaces of the wing

assuming that the flow in the boundary layer is fully laminar.

$($ii$)$ During testing of the UAV, small bolts on the leading edge of the wing loosen

and the wing leading edge starts vibrating. By how much, if at all, could this

change the skin friction drag force?

For air take the following properties: kinematic viscosity

u $=1\mathrm{.}56810-5$m$2$

$.$s$-1$

$,$

viscosity $\backslash$mu $=1\mathrm{.}84610-5$

kg$.$m$-1$

$.$s$-1$

$,$ density $\backslash$rho $=1\mathrm{.}177$kg$.$m$-3$

$.$