Determine Reynolds number for small viscosity case Laminar flow has mixing only by molecular diffusion. Turbulent flow has mixing due to large scale fluctuations. Reynolds number is a measure of whether flow is laminar or turbulent. Classification of viscous flow as laminar or turbulent dictates how the flow is analyzed. If the entry length is greater than the tube length, is the flow fully developed

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.