On a hot day (t = 30°c), a truck moves along the highway at 29 m/s. the flat side of the truck is treated as a simple, smooth flat plate boundary layer to first approximation. estimate the x-location along the plate where the boundary layer begins to transition to turbulence. how far downstream from the beginning of the plate do you expect the boundary layer to become fully turbulent? the density and viscosity of air at t = 30ºc are 1.164 kg/m3 and 1.872 × 10–5 kg/m·s, respectively..

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w