Hi Max,
> I'm working with version 3.0 and have made the following changes. > > Old: > > using LinearSolver = Dumux::AMGBackend<TypeTag>; > auto linearSolver = std::make_shared<LinearSolver>(leafGridView, > fvGridGeometry->dofMapper()); > > New: > > using LinearSolver = Dumux::UMFPackBackend; > auto linearSolver = std::make_shared<LinearSolver>(); > > Is that correct? Yes. > With these changes it is possible to calculate with more than 2000 > elements, unfortunately the grading does not work. Can you post the complete output? > But I have found that if the solid thermal conductivity in the outflow > area is increased to at least 0.2, superheated steam is calculated. If > the solid thermal conductivity is adjusted to the same value as the > porous area (30), the results will show a realistic behavior. > > Now I'm wondering, why the change in the solid thermal conductivity in > the outflow area has such a big impact on the evaporation in the > porous area. > > Do you have any suggestions why that happens? No, but maybe others can jump in who are more familiar with the nonequilibrium models. Kind regards Bernd Zitat von "Flemisch, Bernd" <bernd.flemi...@iws.uni-stuttgart.de>: > Hi Max, > > you should first check if the problem is the linear solver by > switching to a direct solver. If you use Dumux 2.x, that's setting a > SET_TYPE_PROP(YourTypeTag, LinearSolver, UMFPackBackend<TypeTag>); > in the problem file, for 3.0 you have to change the corresponding > line in the main file. > > Let us know how this changes things and we can decide what to do next. > > Concerning the other issue about only one affected element, I'd > proceed as you and use a graded mesh to check if it spreads over > more elements once it's fine enough. > > Kind regards > Bernd > > > > On Thu, Mar 7, 2019 at 7:53 PM +0100, "Maximilian Johannes Lueftner" > <lueft...@mail.uni-paderborn.de<mailto:lueft...@mail.uni-paderborn.de>> > wrote: > > > > Dear DuMuX experts, > > i have adapted the simulation from the test folder > „dumux/test/porousmediumflow/mpnc/implicit/thermalnonequilibrium" . > > I used the YASPGrid for 1D with grading: > struct Grid { using type = > Dune::YaspGrid<1, Dune::TensorProductCoordinates >; }; > > With 800 Elements (400 in the porous domain and 400 in the outflow) > and with 1600 Elements it works fin, but with more than 2000 Elements > I get the following error message: > > Solve: M deltax^k = rNewton: Caught exception: "FMatrixError > [luDecomposition:/.../dumux/dune-common/dune/common/densematrix.hh:909]: > matrix is singular" > > If I try it with grading I receive the following error message: > > Solve: M deltax^k = rNewton: Caught exception: "NumericalProblem > [solveLinearSystem:/.../dumux/nonlinear/newtonsolver.hh:354]: Linear > solver did not converge" > > > Could you please help me to solve this problem? I tried it myself > several times but was not successful until now. > > I suspect that an even finer grid is needed, since only in the last > element of the porous area does the temperature of the vapor increase > dramatically. Or does this behavior have a different reason? When the > heat flow is doubled, however, superheated steam is still calculated > only in the last element. > > > Thank you in advance and best regards, > > Max > > _______________________________________________ > Dumux mailing list > Dumux@listserv.uni-stuttgart.de > https://listserv.uni-stuttgart.de/mailman/listinfo/dumux _______________________________________________ Dumux mailing list Dumux@listserv.uni-stuttgart.de https://listserv.uni-stuttgart.de/mailman/listinfo/dumux
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