Question: In the effort to find the best way to cool a smooth thin-walled copper tube, an engineer decided to flow air either through the tube or across the outer tube surface. The tube has a diameter of 5 cm, and the surface temperature is maintained constant. Determine
(a) the convection heat transfer coefficient when air is flowing through its inside at 25 m/s with bulk mean temperature of 50°C and
(b) the convection heat transfer coefficient when air is flowing across its outer surface at 25 m/s with film temperature of 50°C.