2010/1/28 Igor <[email protected]>: > Dear fipy users and developers, > > I have a spherical symmetric problem, so I can use Grid1D mesh, but need to > multiply coefficients in diffusion-convection problem by r^2 and also add > external one like 1/r^2, i.e. > > df/dt = 1/r^2 d/dr (r^2 D df/dr) - 1/r^2 d/dr (r^2 u f)
The best way is to just being the r^2 expression inside the TransientTerm. TransientTerm(r**2) == DiffusionTerm(... etc Multiplying by the coefficient does work, but I'm not sure of the equivalence of the discretization between "multiplying by the coefficient" and "taking the r^2 inside the transient term". > I managed to provide r^2 in "internal" coefficients, but failed to provide > 1/r^2 in "external" ones (i.e. something like (1/r**2)*DiffusionTerm). I > then tested to put some CellVariable before the Term as was advised to do > earlier and the script failed again. It should work, but as I said, you don't need to worry about it now. Cheers -- Daniel Wheeler
