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IDProjectCategoryView StatusLast Update
0002697OpenFOAMBugpublic2017-09-12 14:45 Assigned Tohenry  
Status closedResolutionfixed 
PlatformGNU/LinuxOSUbuntuOS Version14.04
Summary0002697: Phase fraction close to the wall presents an almost constant value along several cells for different mesh refinements.
DescriptionI am replicating a simplified version of the laminar bubbling fluidised bed case with twoPhaseEulerFoam solver. No gas feed is considered and at this stage alphaMax is assumed to be 1 (so no upper limit is given to MULES). Therefore, it is expected that the fluidized bed will compact due to the effect of gravity.
However, I found that the phase fraction of the settling phase predicts almost the same value in the first 4 cells close to the bottom wall, which does not seem physical. The phase fraction in these 4 cells increase during the simulation, but they always remain with similar values.
Furthermore, this behavior is also found when running the case with a finer mesh, with the same 4 cells having an almost constant value for "alpha.particles".
Steps To ReproduceJust run the case provided with twoPhaseEulerFoam solver and plot quantitatively the dispersed phase fraction over a vertical line.
Additional InformationThe case folder used to replicate this situation is attached. An image is also provided in the folder which plots the phase fraction of the dispersed phase as function of the cell number along the y direction. Three different mesh refinement cases are presented and the results are given at t=2s (even though a similar trend can be observed throughout the entire simulation). It can be seen that all the mesh refinements seem to have a region with an almost constant phase fraction value for a specific number of cells, close to the bottom wall. Furthermore, for the two meshes with higher refinement, this constant phase fraction region affects 4 cells in both cases.
TagsMULES, multiphase


related to 0002470 resolvedhenry MULES prevents settling in lower cells. 


2017-09-11 16:01


myFluidisedBed.tgz (144,045 bytes)


2017-09-11 16:28

manager   ~0008750

This issue is probably the same as #2470, please upgrade to OpenFOAM-dev, re-test and follow the discussions in #2470 to see if the same approach resolves the problem.


2017-09-11 20:30


OpenFOAMdev.png (58,416 bytes)   
OpenFOAMdev.png (58,416 bytes)   


2017-09-11 20:30

reporter   ~0008752

@Henry The problem does not occur in the latest OpenFOAM-dev version. I checked it out right now (see picture). So I guess Chris should either shift to latest version or implement the commits himself.



2017-09-12 14:45

manager   ~0008763

Already resolved in OpenFOAM-5.? and OpenFOAM-dev

Issue History

Date Modified Username Field Change
2017-09-11 16:01 New Issue
2017-09-11 16:01 File Added: myFluidisedBed.tgz
2017-09-11 16:01 Tag Attached: MULES
2017-09-11 16:01 Tag Attached: multiphase
2017-09-11 16:28 henry Note Added: 0008750
2017-09-11 16:29 henry Relationship added related to 0002470
2017-09-11 20:30 Shorty File Added: OpenFOAMdev.png
2017-09-11 20:30 Shorty Note Added: 0008752
2017-09-12 14:45 henry Assigned To => henry
2017-09-12 14:45 henry Status new => closed
2017-09-12 14:45 henry Resolution open => fixed
2017-09-12 14:45 henry Fixed in Version => 5.0
2017-09-12 14:45 henry Note Added: 0008763