Problem 6.016 a fan that can provide air speeds up to 50 m/s is to be used in a low-speed wind tunnel with atmospheric air at 25ºc. if one wishes to use the wind tunnel to study flatplate boundary layer behavior up to reynolds numbers of 108, what is the minimum plate length that should be used? at what distance from the leading edge would transition occur if the critical reynolds number were 5 × 105?

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.