Hi Dennis, Thank you very much! It solved my problem.
Best wishes, Tri Dat De : Dumux [mailto:[email protected]] De la part de Dennis Gläser Envoyé : vendredi 9 décembre 2016 14:24 À : [email protected]; [email protected] Objet : Re: [DuMuX] Velocity computation with box method on 2D-in-3D grid Hi Tri Dat, thank you very much for pointing this out. I just found a bug in the BoxFVElementGeometry. The normal vector on interior faces was not scaled by the correct area, thus ending up in wrong fluxes. Could you please check out the branch fix/boxnetworkgridnormalcomputation and try again? Hopefully this solves the problem! Best wishes, Dennis On 08.12.2016 14:32, Tri Dat NGO wrote: Hi Timo, 1. I declared permeability as a scalar. I have not yet tested the case of tensor permeability in world coordinates. I will do that. 2. To simulate advection-diffusion model in Dumux, I simply modified properties of fluid in the file in "dumux/material/fluidsystems/" . Concretely, I desactivated all pressure-dependence of density, viscosity and diffusion coefficient. In the isothermal condition, fluid density, viscosity and diffusion coefficient are constant. The velocity V is computed by Darcy's law, so it will also be constant. 3. I was not clear. Y in "Y = Ymin" or "Y= Ymax" is Y-coordinate. 4. To estimate the velocity, I looked at the concentration front and compute it by hand. Kind regards Tri Dat 2016-12-08 13:56 GMT+01:00 Timo <[email protected]<mailto:[email protected]>>: Hi Tri Dat, this is interesting. I have a few more questions to narrow it down. How did you specify the permeability? In world coordinates as tensor? As scalar? And why do you need it in your advection-diffusion equation? (maybe I understood wrongly and you actually compute the velocity using Darcy's law, so the full 1p2c model?) What do you mean by "Y" in your boundary conditions? How did you observe the velocity? Did you use the velocity calculation feature of Dumux? Or did you just look at the concentration front and compute it by hand? Best wishes Timo On 06.12.2016 14:11, Tri Dat NGO wrote: Hi Dumux developers, I have just done some simulations of the advection-diffusion equation (Figure_1, simplified from 1p2c model in Dumux) on three 2D-in-3D grids. Case (A), the first grid resides on the XOY plane, the mesh (B) and (C) are obtained by rotating the mesh (A) around Y-axis by an angle \alpha with cos (\alpha) =1/sqrt(5)) and 90°, repectively. Consequently, the mesh (C) resides on the YOZ (see the Figure_2, A: white, B: blue, C: yellow). */ Initial condition: P=P0, c = 0. */ Boundary conditions: - Y = Ymin: P=2P0, c=C0, - Y = Ymax: P=P0, c=0 (It means that the flow is along Y-axis) - No-flux Neumann condition for the remaining boundaries. Viscosity is constant, gravity is neglected. The diffusion effect is very smaller than the convection one (V*L/D ~1E7). Since gravity is neglected, in principle, the result of these three simulations should be the same: the front of the concentration profile travels with a velocity V. But, curiously, this is not the case. The travelling velocity of front of the concentration curve in the case (A) is equal to \sqrt(5) time in the case (B). Furthermore, in the case (C), there was a convergence problem: Linear solver did not converge. It seems that the permeability in the case (B) Kyy(B) equal to 1/sqrt(5) of the one in the case (A), Kyy(A), and Kyy(C) = 0. I think that it may be a bug (?) in the transformation from global to normal vector cooridnate of the reference element in the box method on 2D-in-3D mesh when using FoamGrid. Could you please check it and confirm me? I'm sorry for this long email and I hope I was clear with that. Kind regards, Tri Dat _______________________________________________ Dumux mailing list [email protected]<mailto:[email protected]> https://listserv.uni-stuttgart.de/mailman/listinfo/dumux _______________________________________________ Dumux mailing list [email protected]<mailto:[email protected]> https://listserv.uni-stuttgart.de/mailman/listinfo/dumux _______________________________________________ Dumux mailing list [email protected]<mailto:[email protected]> https://listserv.uni-stuttgart.de/mailman/listinfo/dumux __________________________ Avant d'imprimer, pensez à l'environnement ! Please consider the environment before printing ! Ce message et toutes ses pièces jointes sont confidentiels et établis à l'intention exclusive de ses destinataires. Toute utilisation non conforme à sa destination, toute diffusion ou toute publication, totale ou partielle, est interdite, sauf autorisation expresse. IFP Energies nouvelles décline toute responsabilité au titre de ce message. This message and any attachments are confidential and intended solely for the addressees. Any unauthorised use or dissemination is prohibited. IFP Energies nouvelles should not be liable for this message. __________________________
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