Answer Happy

0.3 0.21 Pr = 0.01 01 6 8 10 12 14 16 18 20 22 24 Pr=0.01 0.2 0.7 an 8 10 12 14 16 18 20 22 0.6 Pr = 0.01 1.0 0.5 Pr-0.01 0.4 0.8 0.72 PROBLEM 4 (15 points, 2.5 points for a and b and 10 for c) The shown plots are the solutions of velocity profiles (left) and temperature profiles (right) for the free convection boundary layer condition on isothermal, vertical surface under laminar flow condition. (a) Please explain the physical meaning of y-axis and (b) why the curves converge at about 5-6 for velocity (left figure) for Pr <0.72 while temperatures (right figure) do not have the trend? (c) Considering this vertical plate is 1 meter long at a 3 4 uniform temperature of 100 °C. The - (2) plate is suspended in quiescent air that is 20 °C. Please calculate the velocity of boundary layer thickness and maximum upward velocity at middle of the plate. PROPERTIES: Air (T=323K): v=18x10 kg/s'm, Pr=0.7 S' O) = Ger12 0.72 0.3 0.6 2 10 100 -1000 T = (T-T/T,- 0.2 0.4 2 10 100 0.1 0.2 1000 0 2 5 6 7 0 0 1 2 3 4 5 6 n- n (a) (b)