A tracer diffuses from the (circular) boundary of the domain for a given time. This test case compares the solutions obtained using the implicit and the explicit diffusion schemes.
The radial tracer profiles for both schemes are illustrated in Figure 43.
A non-homogeneous concentration confined in an annular gap relaxes by diffusion to the equilibrium state. This test case compares the solutions obtained using the implicit and the explicit diffusion schemes over a concentration. The total amount of the species is preserved with both schemes to within 2× 10−7.
The radial concentration profiles for both schemes are illustrated in Figure 44.
