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Unformatted text preview: T = 288 K, air temperature T a is fixed, = 1.2 kg m-3 , C p = 1004 J kg-1 K-1 , C D = 2 x 10-3 , and U = 5 m s-1 . 4. (Hartman) Air with a temperature of 27 o C moves across a dry parking lot at a speed of 5 m s-1 . The insolation at the surface is 600 W m-2 and the downward longwave radiation at the ground is 300 W m-2 . The longwave emissivity of the surface is 0.85, and the albedo of the asphalt surface is 0.10. What is the surface temperature in equilibrium ? What is the surface temperature if the asphalt is replaced with concrete with an albedo of 0.3 and the same emissivity ? The air density and drag coefficient are as in Problem 3. Hint : Linearize the blackbody emission around the air temperature T a and use the surface energy equation to show that T s " T a = S # (0) (1 " $ s ) + % F # (0) " & T a 4 ( ) C p C D U + 4 T a 3...
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This homework help was uploaded on 04/02/2008 for the course ATMO 324-501/50 taught by Professor Saravanan during the Fall '08 term at Texas A&M.
- Fall '08