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IDProjectCategoryView StatusLast Update
0003842OpenFOAMFeaturepublic2022-06-06 17:58
ReporterszamaniAssigned Tohenry 
PrioritynoneSeverityfeatureReproducibilityalways
Status closedResolutionsuspended 
PlatformUnixOSLinuxOS VersionCentos Linux 7
Product Version9 
Fixed in Version 
Summary0003842: Incorrect gravity in DPMFoam solver
DescriptionI believe DPMFoam solver in OpenFOAM (versions 7 - 9) is incorrect. The gravity component in UEqn.H and pEqn.H files must be multiplied by the phase fraction (alphac).
Steps To ReproduceYou can run the Lagrangian-Goldschmidt tutorial by DPMFoam but with water properties. The pressure readings will be off.
Additional InformationThis can be easily fixed by multiplying gravity component with alphac or the interpolated version (alphacf).
TagsNo tags attached.

Activities

henry

2022-05-29 14:42

manager   ~0012602

The DPMFoam solver does not exist in OpenFOAM-9.

> You can run the Lagrangian-Goldschmidt tutorial by DPMFoam but with water properties. The pressure readings will be off.

In what way are the "pressure readings ... off"?

> This can be easily fixed by multiplying gravity component with alphac or the interpolated version (alphacf).

This would make the handling of the pressure and gravity inconsistent.

Could you provide much more detail about the results, the expected results and the change you propose?

szamani

2022-05-29 15:59

reporter   ~0012603

Based on the momentum equation, the gravity force in momentum equation must be multiplied by alphac. However, in the UEqn.H, the gravity force is never multiplied by fluid-phase volume fraction.
These files are from OpenFOAM 7 version.
I could of course be wrong, but I checked the way the interFoam handles UEqn.H and pEqn.H (interFoam basically uses density in the same exact way as alphac, and there, we have the gravity force and density multiplied.
Of course I could be wrong, I appreciate your time and consideration.

MomentumEqn.PNG (7,910 bytes)
MomentumEqn.PNG (7,910 bytes)
UEqn.PNG (78,258 bytes)
UEqn.PNG (78,258 bytes)

henry

2022-05-29 16:26

manager   ~0012604

We had serious problem with numerical noise when the buoyancy and pressure terms were multiplied by the phase-fraction which of course is noisy as it comes from the Lagrangian phase.
Also it is not clear how the pressure term should be treated within the particulate phase and hence how it should be treated in the continuous phase; it is not equivalent to VoF or Euler-Euler.

Can you provide a set of test-cases which demonstrate the advantage of multiplying the buoyancy and/or pressure terms by the continuous phase fraction?

henry

2022-06-06 17:57

manager   ~0012625

Pending feedback, test-cases and Lagrangian phase pressure closure model.

Issue History

Date Modified Username Field Change
2022-05-29 14:23 szamani New Issue
2022-05-29 14:42 henry Note Added: 0012602
2022-05-29 15:59 szamani File Added: MomentumEqn.PNG
2022-05-29 15:59 szamani File Added: UEqn.PNG
2022-05-29 15:59 szamani Note Added: 0012603
2022-05-29 16:26 henry Note Added: 0012604
2022-06-06 17:57 henry Assigned To => henry
2022-06-06 17:57 henry Status new => closed
2022-06-06 17:57 henry Resolution open => suspended
2022-06-06 17:57 henry Note Added: 0012625
2022-06-06 17:57 henry Priority high => none
2022-06-06 17:57 henry Category Bug => Feature
2022-06-06 17:57 henry View Status private => public
2022-06-06 17:58 henry Severity major => feature