CHM ENG 150A Midterm: cheme150A-sp2012-mt2-Muller-soln
8 Jan 2019
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1. (20 points) the first flight of a fully controlled heavier-than-air craft was constructed and performed by the wright brothers in a glider in 1902. The glider depicted below had a wingspan of 9. 78 m and each wing had an area of 28 m2. We are interested in determining the total friction drag on the two wings, which is related to the boundary layer. The boundary layer is actually laminar until rex exceeds approximately 2 x 105, after which it transitions to a turbulent boundary layer. The turbulent boundary layer thickness can be calculated using: and the wall shear stress is given by: The properties of air at 25 c are = 1. 8 x 10-5 pa s, = 1. 2 kg/m3: determine transition point xtr along the length of a wing. 4. 58 mm tr tr: assuming a turbulent boundary layer, estimate the total friction drag on the two wings.
