> Hi Konrad,
>
> I figured out my error. I was imposing constraints differently on the
> advection matrix than from the other matrices. I fixed it by not using the
> constraints.local_to_global() function and just computing the full matrix
> and using constraints.condense() on the system
Hi Konrad,
I figured out my error. I was imposing constraints differently on the
advection matrix than from the other matrices. I fixed it by not using the
constraints.local_to_global() function and just computing the full matrix
and using constraints.condense() on the system matrix after adding
Hi Gary,
I've been using an implicit scheme, but also tried treating the advection
> term explicitly. Specifically, I'm solving the system
> (Mij + k*d*Aij + k*Bij) Unj = Mij Un-1j + Fn-1
> where M is the mass matrix, A is the laplace matrix, B is the advection
> matrix, k is the time step,
Hi Gary,
I'm trying to solve a time dependent advection-diffusion equation with
> periodic boundary conditions. Just a simple du/dt = D \nabla^2 u - v \dot
> \grad u for now. I use a large diffusion constant, so stability shouldn't
> be an issue. The solution behaves normally in the bulk, but
