Dear Alex, Thanks for your reply!
"I am not sure if I got you right, you want to have a fixed Saturation (Dirichlet) for one phase and inject another phase? In Dumux you can choose the equation that should be replaced by the Dirichlet condition with the call: setDirichlet(int pvIdx, int eqIdx) The equation you choose cannot be assigned to a Neumann BC anymore. The rest of the equations can be assigned as Neumann BCs. Maybe you could list the type of BC you would like to have for each equation?" I found a workaround to calculate the fluxes at the outlet of my system, so now I set Dirichlet conditions at the inlet and solDependentNeumann conditions at the outlet. This should work. "For the box method the outflow condition uses the gradients evaluated at the integration point of the boundary face to calculate the flux out of the domain for the equation you choose." If I understand correctly this means that whatever is on an outflow boundary is allowed to flow out or into the system. So if we assume pure fickian diffusion and the concentration in the domain is higher than on the boundary stuff will flow out while it is vice versa if the concentration is lower. If that is the case, what exactly is the difference to a Dirichlet boundary condition? As far as I see, with this type of boundary condition I would keep e.g. a concentration on the boundary constant. Am I correct? Best regards Georg Von: Dumux [mailto:[email protected]] Im Auftrag von Alexander Kissinger Gesendet: Donnerstag, 30. Juli 2015 08:53 An: DuMuX User Forum Betreff: Re: [DuMuX] Boundary conditions Dear Georg, I am not sure if I got you right, you want to have a fixed Saturation (Dirichlet) for one phase and inject another phase? In Dumux you can choose the equation that should be replaced by the Dirichlet condition with the call: setDirichlet(int pvIdx, int eqIdx) The equation you choose cannot be assigned to a Neumann BC anymore. The rest of the equations can be assigned as Neumann BCs. Maybe you could list the type of BC you would like to have for each equation? Secondly, I stumbled across the outflow boundary condition recently what is the physical idea behind this type of boundary condition? For the box method the outflow condition uses the gradients evaluated at the integration point of the boundary face to calculate the flux out of the domain for the equation you choose. Best regards Alex On 29.07.2015 16:14, [email protected]<mailto:[email protected]> wrote: Hello Dumux, I am working with the (implicit, box) mpnc-model with a 2p5c fluidsystem and I would like to specify the following inlet boundary conditions to my system: gas pressure, saturation and phase composition. This can be done with a Dirichlet condition and it works fine. But additionally, I would like to set the gas flux into the model domain (basically the pressure gradient) which would mean setting a Neumann boundary condition. Is there a way to do this in Dumux? Secondly, I stumbled across the outflow boundary condition recently what is the physical idea behind this type of boundary condition? Thanks for your help! Georg Futter -------------------------- German Aerospace Center (DLR) Institute of Engineering Thermodynamics | Computational Electrochemistry | Pfaffenwaldring 38-40 | 70569 Stuttgart Dipl.-Ing. Georg Futter | Ph.D. student Telefon 0711/6862-8135 | [email protected]<mailto:[email protected]> www.DLR.de<http://www.dlr.de/> _______________________________________________ Dumux mailing list [email protected]<mailto:[email protected]> https://listserv.uni-stuttgart.de/mailman/listinfo/dumux
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