Problem 2: You are designing a heated flat aluminum plate for an experiment in my wind tunnel. Air at27°C and 10 m/s flows over the plate, which is kept at a constant temperature of 77°C by internal heaters. (a) Assuming that the boundary layer develops naturally (i.e. is NOT tripped to turbulence), how far along the plate will the boundary layer remain laminar? Use a transition Reynolds number of 5x10S. Ans:0.92 m (b) If the plate is 2 meters long, calculate the average Nusselt number over the entire plate. (Hint: Eqs7.38 and 7.39 will be useful; these same egs are on the provided equation sheet in the Practice Exammodule). Ans: 1444 (c) How much heat needs to be supplied to the plate, if it is 1.2 m wide? (d) If we decided to trip the boundary layer to turbulence (i.e., Rex.crit=0 and A=0), how much heat would need to be supplied to the plate? How does this compare to part (c)? Why is it different? Partial Ans:3.7 kW

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