Hello,
I am running a fairly simple 1p porous flow simulation which is on a 2D
rectangular grid. In a particular case I came at, the initial and
boundary conditions, as well as spatial parameters, do not depend on the
"y" coordinate, only on "x". There is no gravity and the flow is
designed to be strictly horizontal. So I naturally expect the results to
be essentially 1-dimensional, i. e. the solution at any moment in time
should be a function of x and not of (x,y). But after some time, I get
irregularities over the "y" axis, that I think come from the linear
solver. They are small, but they cause further inconsistencies.
I tried AMGBiCGSTABBackend, ILU0BiCGSTABBackend and UMFPackBackend and
the problem persists. I tried to play with the convergence criteria
(LinearSolver.ResidualReduction, Newton.MaxAbsoluteResidual,
Newton.ResidualReduction, Newton.MaxRelativeShift). Some of them helped
to mitigate the problem, but did not eliminate it. Strictening the
criteria too much kills the convergence.
Are there any options that I can set for solvers to force them to
respect the symmetry of the problem over one axis?
(I know that I can use a 1D grid and have a consistent solution, but
that will not help in 2D situations where I have part of the system
depending on (x,y) and the other part depending only on x.)
Best regards,
Dmitry
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