Liz,
Is your equation of the form:
d(phi)/d(t)= D/(r^2) d^2(phi)/(dr)^2
If so, then I believe the implicitDiffusionTerm is approriate. You can
change the diffusion coef. by setting it as a cellVariable. If this is
a 1-D radial problem, then I think you'll need to modify D to account
for the geometry of the problem, if you have not already accounted for this.
Have you looked at the diffusion examples in the users guide? I found
them pretty helpful.
I'm no expert...perhaps someone with more experience using FiPy can
answer this better.
Andy
On Tue, 10 Apr 2007, Elizabeth Tseng wrote:
Hi,
I'm new to both fipy and PDEs. I'm trying to construct a transient term
that looks like this:
\frac{\partial PHI}{\partial t} = (D / (r^2)) \frac{r^2 \frac{\partial
PHI}{\partial r}}{\partial r}
I know the left hand term should be a Transient Term. But what about the
right hand term? The coefficient, instead of being a fixed constant D, is D /
(r^2)...
Thanks,
Liz
