Re: Boussinesq Equations

It certainly won't be that simple. You'll need to look through the literature to figure it out. I suspect it will require re-introducing a pressure into the equations and then transforming the continuity equation into an equation for pressure. On Thu, Oct 11, 2018 at 4:06 AM fgendr01 wrote: > > Th

Re: Boussinesq Equations

Thanks Daniel for your answer, I used the continuity equation (nabla vector velocity) to obtain the equation in temperature. But actually, maybe we should use it as a constraint to my problem. But now, how can I create this constraint ? with a new equation ? I tried : velocity.divergence == 0 but

Re: Boussinesq Equations

Don't you still have a $\nabla . \vec{u} = 0$ equation though? It doesn't go away. That equation becomes like a constraint. https://www.comsol.com/multiphysics/boussinesq-approximation On Wed, Oct 10, 2018 at 5:58 AM fgendr01 wrote: > > Hi Daniel, > Thank you for your answer. > I thank you for t

Re: Boussinesq Equations

Hi Fabien, I looked over your problem and I haven't been able to debug it. I tried various combinations of constraints and I'm not sure why it's becoming nonphysical (dT >1 or dT < -1). It would require getting into the code and looking at the numbers in the offending cells. One thing that worrie

Re: Boussinesq Equations

Fabien - I don't know where the problem lies, but my recommendation would be to systematically take the problem back toward the code I previously gave you. While that code didn't produce the image you were looking for, the behavior seemed consistent and it wasn't unstable. As far as I can tell

Re: Boussinesq Equations

Yes I tried without kinematic boundary conditions and there is no difference ! Maybe the scheme is not stable. Other ideas ? Fabien > Le 17 sept. 2018 à 22:27, Thibault Bridel-Bertomeu > a écrit : > > Have you tried without the kinematic boundary conditions ? Just constrain T > and dT/dn, wha

Re: Boussinesq Equations

Hi again Fabien, Well, I would say that physically it makes sense. With such boundary condition, I think the problem is well posed. Now it is all about the numerics. Have you tried ? What does the solver yield ? Cheers Thibault Le lun. 17 sept. 2018 à 21:49, fgendr01 a écrit : > Thanks Thibault

Re: Boussinesq Equations

Thanks Thibault, You’re right, the top ans the bottom walls are adiabatic and I tried to put velocity conditions. What do you think about these conditions : # Boundary Conditions T.constrain(Tmax, mesh.facesLeft) T.constrain(Tmin, mesh.facesRight) T.faceGrad.constrain(0, mesh.facesTop) T.faceGrad

Re: Boussinesq Equations

Thanks a lot Jon. I appreciate your help. I will try to apply your remarks but I will certainly still need your help again ;-) to develop the code. Thanks again. Fabien > Le 15 août 2018 à 19:46, Guyer, Jonathan E. Dr. (Fed) > a écrit : > > Fabien - > > I think the code below should get you

Re: Boussinesq Equations

Fabien - I think the code below should get you going. The changes I made were: - `xVelocity` and `zVelocity` changed to rank-0 CellVariables. FiPy *always* solves at cell centers. - Created a rank-1 FaceVariable to hold the velocity. The cell components must be interpolated and manually insert