The roof of a refrigerated truck compartment is of composite construction, consisting of a layer of foamed urethane insulation t2=50 mm, ki = 0.026 Wm. sandwiched between aluminum alloy panels (t1=5mm, kp =180Wm ) the length and width of the roof are L=10m and W=3.5m respectively., and the temperature of the inner surface is T=-10degree C. consider conditions for the for which the truck is moving at a speed of V=105kmh, the air temperature is T infinity = 32degree C and the solar irrigation is Gs=750 wm². turbulent flow may be assumed over the entire length of the roof.