View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001378 | OpenFOAM | Bug | public | 2014-08-20 14:18 | 2014-10-15 10:20 |
| Reporter | Assigned To | will | |||
| Priority | normal | Severity | crash | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Summary | 0001378: Instability in Schaeffer frictional stress | ||||
| Description | Applying the Schaeffer frictional stress model in twoPhaseEulerFoam results in the following error message: --- #0 Foam::error::printStack(Foam::Ostream&) at ??:? #1 Foam::sigFpe::sigHandler(int) at ??:? #2 in "/lib/x86_64-linux-gnu/libc.so.6" #3 in "/lib/x86_64-linux-gnu/libm.so.6" #4 pow in "/lib/x86_64-linux-gnu/libm.so.6" #5 Foam::pow(Foam::Field<double>&, Foam::UList<double> const&, double const&) at ??:? #6 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::pow<Foam::fvPatchField, Foam::volMesh>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::dimensioned<double> const&) at ??:? #7 Foam::dragModels::WenYu::CdRe() const at ??:? #8 Foam::dragModels::GidaspowErgunWenYu::CdRe() const at ??:? #9 Foam::dragModel::K() const at ??:? #10 Foam::BlendedInterfacialModel<Foam::dragModel>::K() const at ??:? #11 Foam::twoPhaseSystem::dragCoeff() const at ??:? #12 at ??:? #13 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #14 at ??:? --- The tutorial case will however run with Schaeffer frictional stress if alphaMinFriction is changed from 0.5 to 0.6. | ||||
| Steps To Reproduce | This can be reproduced in the RAS/fluidisedBed tutorial case simply by changing the frictional stress model from JohnsonJackson to Schaeffer (all other values unchanged) | ||||
| Additional Information | Discussion on the issue http://www.cfd-online.com/Forums/openfoam/139956-applying-schaeffer-frictional-stress.html#post506837 | ||||
| Tags | No tags attached. | ||||
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The Schaeffer model generates an exponentially increasing frictional pressure for particulate phase fractions above the specified alphaMinFriction of 0.5. The RAS setup also includes a particle pressure which allows the particulate fraction to reach 0.62. At this value, the frictional pressure generated by the Schaeffer model is very large, and presumably not physical. You've already found the answer to the instability; increasing alphaMinFriction. Models work with some coefficients, and are unstable with others. If you have data which suggests the Schaeffer model is wrong, or you can spot something incorrect in the implementation, then please feel free to re-open this report. As that information is currently lacking, I'm marking this as closed. NB: Re the CFD Online thread, frictionalPressurePrime is the derivative of the frictional pressure with respect to the volume fraction. The Schaeffer model is implemented consistently in this respect. |
