Gradient of Ground Temperature in Response to Cold Winds
In the fall, winds cool the ground. This Demonstration shows the evolution of the ground temperature profile versus time (in seconds) for various values of thermal diffusivity (expressed in ), convective heat transfer coefficient (expressed in ), and heat conduction coefficient (expressed in ).[more]
The temperature of the ground is assumed to be initially at 15.6°C and the cold wave reduces the temperature of the air to -17.8°C. The problem is that of an unsteady-state heat conduction in a semi-infinite solid, which has the analytic solution given in . The color gradation from blue to red represents the gradient of ground temperature.[less]
 C. J. Geankoplis, Transport Processes and Unit Operation, 3rd ed., Englewood Cliffs: Prentice–Hall, 1993.