Question

Define the term Nusselt number and explain its significance in the case of forced convection heat transfer.

Atmospheric air at $T_\infty$ = 275 K and a free-stream velocity $u\infty$ = 20 m/s flows over a flat plate L = 1.5 m long that is maintained at a uniform temperature T_w = 325 K.

1. Calculate the average heat transfer coefficient h_m over the region where the boundary layer is laminar.
2. Find the average heat transfer coefficient over the entire length L = 1.5 m of the plate.
3. Calculate the total heat transfer rate Q from the plate to the air over the length L = 1.5 m and width W = 1m

Assume transition occurs at R₂ = 2 x10⁵.