Nonsteady-state heat conduction in a cylinder obeys the following PDE:

,

where is the thermal diffusivity coefficient expressed in , is the temperature in , and is the radial position in meters.

The initial condition and boundary conditions are

(initial temperature);

(the temperature at the cylinder surface is kept constant);

(symmetry condition).

This Demonstration shows the temperature profile inside the cylinder at different instants for values of the thermal diffusivity coefficient specified by the user.