Air at ( , ) streams at over a flat plate

PHYSICS · Multi-part · Fermi University Physics · Fluids & Continuum Physics · Viscous flow and dynamical similarity · Viscous flow and dynamical similarity

Fluid Dynamics, Ch The boundary layer: Prandtl's equations and the Blasius solution

Problem

Air at 20∘C20^{\circ}\mathrm{C} (ρ=1.20 kg m−3\rho = 1.20\,\mathrm{kg\,m^{-3}}, ν=1.51×10−5 m2 s−1\nu = 1.51\times10^{-5}\,\mathrm{m^2\,s^{-1}}) streams at U=15 m s−1U = 15\,\mathrm{m\,s^{-1}} over a flat plate. The layer is laminar and attached, with no pressure gradient imposed by the outer flow. Using the Blasius results δ99=4.9x/Rex\delta_{99} = 4.9x/\sqrt{Re_x} and Cf=0.664/RexC_f = 0.664/\sqrt{Re_x}, find, at a station x=0.6 mx = 0.6\,\mathrm{m} from the leading edge: ((a)) RexRe_x; ((b)) the 99% thickness δ99\delta_{99}; ((c)) the wall shear stress τw\tau_w; ((d)) the drag per unit width of plate, on one side, over the length from the leading edge to x=0.6 mx = 0.6\,\mathrm{m}.

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