Search Results

User Name Remember Me Password

Page 1 of 2 1 2 >

Showing results 1 to 25 of 40 Search took 0.00 seconds. Search: Posts Made By: alberto

Forum: OpenFOAM Running, Solving & CFD May 9, 2012, 13:37

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto There was a typo that I corrected in my previous... There was a typo that I corrected in my previous post: fvm::Sp(fvc::div(phi), k) should be fvm::Sp(fvc::div(phib), k). Same for epsilon: you should use phib. Also, you don't need to re-compile the...

Forum: OpenFOAM Running, Solving & CFD May 5, 2012, 14:08

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto This seems quite normal. This seems quite normal.

Forum: OpenFOAM Running, Solving & CFD May 5, 2012, 03:10

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Could you check the values of turbulent viscosity? Could you check the values of turbulent viscosity?

Forum: OpenFOAM Running, Solving & CFD May 5, 2012, 02:28

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto First, let me correct one typo: I wrote "Su"... First, let me correct one typo: I wrote "Su" instead of "Sp". If you use fvm::div(phib, epsilon) - fvm::Sp(fvc::div(phib), epsilon) it should work out, since the units are: [phi] = m/s...

Forum: OpenFOAM Running, Solving & CFD May 4, 2012, 23:47

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Those terms are what is in the code already: ... Those terms are what is in the code already: fvm::div(phib, k) and fvm::div(phib, epsilon). The next divergence term has to be discretized as

Forum: OpenFOAM Running, Solving & CFD May 4, 2012, 22:46

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto I am not sure about what equations you are... I am not sure about what equations you are considering. The "standard" mixture turbulent model is usually identical to the single-phase turbulence model, but considering the properties of the...

Forum: OpenFOAM Running, Solving & CFD April 25, 2012, 02:47

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto New developments in terms of multi-fluid models... New developments in terms of multi-fluid models came with 2.x, but not in terms of turbulence modeling. For the limit of beta -> 0, you can probably define a minimum value of alpha in some term...

Forum: OpenFOAM Running, Solving & CFD April 23, 2012, 11:30

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Do you have parts of the system where alpha = 1?... Do you have parts of the system where alpha = 1? If so, the turbulence model implemented in twoPhaseEulerFoam/bubbleFoam is unstable in that limit, since beta -> 0. You might want to consider,...

Forum: OpenFOAM Running, Solving & CFD April 21, 2012, 05:51

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto They seem to implement a simpler form of the... They seem to implement a simpler form of the model than the one from Gosman (in Rusche's thesis they mention that Gosman's model might cause numerical problems).

Forum: OpenFOAM Running, Solving & CFD April 20, 2012, 15:32

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi Matt, the k-epsilon model used in bubbleFoam... Hi Matt, the k-epsilon model used in bubbleFoam is a standard k-eps, modified for the continuous phase. What source term are you referring to?

Forum: OpenFOAM Running, Solving & CFD July 6, 2010, 04:47

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto The turbulence model is the same used in... The turbulence model is the same used in bubbleFoam, and the files are taken from there (check the Make settings). Best,

Forum: OpenFOAM Running, Solving & CFD June 14, 2010, 14:40

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto What you usually do is to limit the k and epsilon... What you usually do is to limit the k and epsilon so that they stay positive, and then limit the "turbulent viscosity ratio", meaning the ratio turbulent viscosity / laminar viscosity of the...

Forum: OpenFOAM Running, Solving & CFD June 13, 2010, 02:34

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, what you notice depends on the fact... Hi, what you notice depends on the fact twoPhaseEulerFoam uses the phase-intensive formulation of the momentum equation. In simple words, the phase momentum equations are re-arranged to remove the...

Forum: OpenFOAM Running, Solving & CFD April 22, 2010, 01:20

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto The only multiphase solver with porous zone... The only multiphase solver with porous zone effect included out of the box is porousInterFoam, which uses the VOF approach. You can of course modify other solvers to account for it. P.S. Please do...

Forum: OpenFOAM Running, Solving & CFD April 19, 2010, 04:00

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Nope :) bubbleFoam doesn't use Gosman's model,... Nope :) bubbleFoam doesn't use Gosman's model, since its equations are troublesome when one phase disappears. The model in bubbleFoam uses an equation based on the "continuous phase" (beta) to...

Forum: OpenFOAM Running, Solving & CFD June 23, 2009, 16:13

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, OK. It should keep in general,... Hi, OK. It should keep in general, not only in the air-water system however. Where there is no continuous phase, the turbulence quantities are definetly too big. A time step of 10^-4...

Forum: OpenFOAM Running, Solving & CFD June 20, 2009, 17:40

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto You're welcome. I actually coded the... You're welcome. I actually coded the limiter in quite a rough manner, and I also added some submodels for gas-liquid flows (bubble pressure term, bubble induced turbulence, some drag correlation...

Forum: OpenFOAM Running, Solving & CFD June 20, 2009, 15:06

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi Raghavendra, an additional hint: check... Hi Raghavendra, an additional hint: check the values of k, epsilon and the turbulent viscosity ratio (nutb/nub) where you have no liquid. I quickly took a look at those, and noticed the turbulent...

Forum: OpenFOAM Running, Solving & CFD June 18, 2009, 15:36

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto It is always interesting to see someone without... It is always interesting to see someone without anything better to do than spamming. User reported. Update: Thanks for the cleanup to the CFD-Online people! :-) Best,

Forum: OpenFOAM Running, Solving & CFD June 18, 2009, 11:50

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, in my experience "multphase" and... Hi, in my experience "multphase" and "non-hex grids" are not a good match. It takes a bit more time to generate a good hex grid, but with the same number of cells the result is typically a lot...

Forum: OpenFOAM Running, Solving & CFD June 17, 2009, 10:20

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, thanks for your reply. I have some... Hi, thanks for your reply. I have some doubt that with that difference in the fluid properties you can use the turbulence model based on the mixture. It sounds quite a strong assumption! ...

Forum: OpenFOAM Running, Solving & CFD June 16, 2009, 02:15

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, no, it's not the unstructured grid. If... Hi, no, it's not the unstructured grid. If the grid is so bad to lead to instabilities you would notice it also in the laminar case. We talked some time ago about stability problems with the...

Forum: OpenFOAM Running, Solving & CFD June 2, 2009, 18:54

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, could you point me to those references?... Hi, could you point me to those references? I'm interested in taking a look at them. Is the melted steel newtonian? Btw, I'm also interested in the comparison, so if you want and can stay in...

Forum: OpenFOAM Running, Solving & CFD June 2, 2009, 16:44

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, increasing the tolerance on pressure is... Hi, increasing the tolerance on pressure is not going to help. It will make the code run a bit faster at the beginning, but you actually want to reduce that tolerance not to propagate errors. ...

Forum: OpenFOAM Running, Solving & CFD June 2, 2009, 13:50

Replies: 99 TwoPhaseEulerFoam and Boundary conditions Views: 22,658 Posted By alberto Hi, the problem is that the density ratio... Hi, the problem is that the density ratio becomes very big (7000 if the other phase is air) in your case, and this is a known reason of instability in the solution algorithm. When you increase the...

Showing results 1 to 25 of 40

Page 1 of 2 1 2 >

Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home General Forums     Main CFD Forum     System Analysis     Structural Mechanics     Electromagnetics     CFD Freelancers     Hardware     Lounge Software User Forums     ANSYS         CFX         FLUENT             Fluent Multiphase             Fluent UDF and Scheme Programming         ANSYS Meshing & Geometry     Autodesk Simulation CFD     AVL FIRE     COMSOL     CONVERGE     Fidelity CFD     FloEFD, FloWorks & FloTHERM     FLOW-3D     OpenFOAM         OpenFOAM News & Announcements             OpenFOAM Announcements from ESI-OpenCFD             OpenFOAM Announcements from OpenFOAM Foundation             OpenFOAM Announcements from Other Sources         OpenFOAM Installation         OpenFOAM Meshing & Mesh Conversion         OpenFOAM Pre-Processing         OpenFOAM Running, Solving & CFD         OpenFOAM Post-Processing         OpenFOAM Programming & Development         OpenFOAM Verification & Validation         OpenFOAM Community Contributions             OpenFOAM CC Toolkits for Fluid-Structure Interaction         OpenFOAM Journal         OpenFOAM Bugs     Phoenics     REEF3D         REEF3D News & Announcements     Siemens         STAR-CCM+         STAR-CD     SU2         SU2 News & Announcements         SU2 Installation         SU2 Shape Design Mesh Generation & Pre-Processing Software     ANSA     enGrid     GridPro     Pointwise & Gridgen Visualization & Post-Processing Software     EnSight     FieldView     ParaView     Tecplot Special Topics     Mesh Generation & Pre-Processing     Visualization & Post-Processing CFD Online Community     Site News & Announcements     Site Help, Feedback & Discussions     CFD-Wiki