Water at a local bulk temperature of 24°C flows at 0.8 m/s through a smooth, 1.5-cm-ID tube that is kept at 30°C and the flow is fully developed. The system is extremely clean and quiet, and the flow stays laminar until a noisy air compressor is turned on in the laboratory. Then it suddenly goes turbulent. Calculate the ratio of turbulent to laminar heat transfer coefficients. Air at 227C flows across the pipe at 20 m/s. Find the pipe wall temperature, assuming the water flow to be turbulent.