Problems
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7.3. Find the heat flux density from your arm, at 33" C, to room air at
22" C if there is no wind (free convection) and if the wind speed is
2 mls.
7.4. Compute the heat loss from a sheep to the air if its fleece is 5 cm
thick and the diameter of the sheep's body (inside the fleece) is 25
cm. Assume the fleece has twice the conductance of still air, the body
temperature is 37" C, the wind speed is 4 mls, and the air temperature
is 5" C.
7.5. Compare thermal conductance of clothing at sea level with conductance at 5000 m elevation. Is elevation likely to have a noticeable
effect on heat loss through clothing?
7.6. In Eq. (7.10) there is no minus sign as in Eq. (7.9). Based on the sign
convention implied by Eq. (7.13), discuss the relationship between
fluctuations of w and T and identify what conditions are associated
with a flux from the soil surface to the atmosphere.
11 1
7.3. Find the heat flux density from your arm, at 33" C, to room air at
22" C if there is no wind (free convection) and if the wind speed is
2 mls.
7.4. Compute the heat loss from a sheep to the air if its fleece is 5 cm
thick and the diameter of the sheep's body (inside the fleece) is 25
cm. Assume the fleece has twice the conductance of still air, the body
temperature is 37" C, the wind speed is 4 mls, and the air temperature
is 5" C.
7.5. Compare thermal conductance of clothing at sea level with conductance at 5000 m elevation. Is elevation likely to have a noticeable
effect on heat loss through clothing?
7.6. In Eq. (7.10) there is no minus sign as in Eq. (7.9). Based on the sign
convention implied by Eq. (7.13), discuss the relationship between
fluctuations of w and T and identify what conditions are associated
with a flux from the soil surface to the atmosphere.