PROBLEM 6.1 KNOWN: Variation of hx with x for laminar flow over a flat plate. FIND: Ratio of average coefficient, h x , to local coefficient, hx, at x. SCHEMATIC:

ANALYSIS: The average value of hx between 0 and x is 1 x C x ∫ h x dx = ∫ x -1/2dx x 0 x 0 C 1/2 = 2x = 2Cx -1/2 x = 2h x .

hx = hx hx Hence,

hx = 2. hx