Question: Let air at a constant velocity of 15mis, a temperature of 300°C, and 1 atm pressure flow along a smooth, flat surface. Let the first 15 cm of the surface be cooled by some internal means to a uniform temperature of 90°C. How does the surface temperature vary for the next 45 cm? The first 15 cm must be treated as a surface temperature-specified problem, while the last 45 cm must be treated as a surface-heat-flux-specified problem.