Answer Happy

Consider two cases involving parallel flow of dry atmospheric air over a flat plate at u∞ = 1 m/s, T=45°C. The plate is being maintained at T = 20°C. In the first case our general criteria of Rex,c = 5 x 105 holds, while in the second case turbulent flow has been tripped at the leading edge (x = 0). Determine a.) whether or not the thermal boundary layers for these two cases would ever cross (i.e., have equal thickness, &, at some equal x location), b.) if so calculate this location from the leading edge (m) and if not calculate the thickness (cm) for each case at 0.1 and 0.2 meters. Hint: for the turbulent thermal boundary layer assume a thickness equal to the viscous boundary layer, St≈ 8.