Afan that can provide air speeds of up to 40 m/s is to be used in a low-speed wind tunnel with atmospheric air at 17◦c. if one wishes to use the wind tunnel to study flat-plate boundary layer behaviour up to reynolds numbers of rex = 107 , what is the minimum plate length that should be used? at what distance from the leading edge would transition, from laminar to turbulent flow, occur if the critical reynolds number were rex, c = 5 × 105 ?