View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0003740 | OpenFOAM | Bug | public | 2021-10-18 14:43 | 2024-07-10 16:57 |
| Reporter | peksa | Assigned To | will | ||
| Priority | normal | Severity | major | Reproducibility | always |
| Status | resolved | Resolution | fixed | ||
| Platform | GNU/Linux | OS | Ubuntu | OS Version | 15.04 |
| Product Version | dev | ||||
| Fixed in Version | dev | ||||
| Summary | 0003740: Misleading pressure difference calculation in activePressureForceBaffleVelocityFvPatchVectorField.C | ||||
| Description | Dear developers, In the boundary condition "activePressureForceBaffleVelocityFvPatchVectorField" a choice for opening a wall/cyclic baffle can be chosen to depend on either force or pressure difference. However, the pressure difference is calculated as an explicit loop over patch faces with no weighting, leading to wrong behavior. See the problematic code snippet below: ------------------------------------------------------------------------- forAll(cyclicFaceCells, facei) { valueDiff += p[cyclicFaceCells[facei]]; } forAll(nbrFaceCells, facei) { valueDiff -= p[nbrFaceCells[facei]]; } Info<< "Pressure difference = " << valueDiff << endl; } if ((mag(valueDiff) > mag(minThresholdValue_)) || baffleActivated_) { .... } ------------------------------------------------------------------------- One should use the same valueDiff definition as for the force but then divide the summed scalar by area to get a weighted difference: valueDiff = valueDiff/gSum(patch().magSf()); An example fix is presented earlier on ESI version: https://develop.openfoam.com/Development/openfoam/-/commit/da6675803b167e7c51c1d2da4d6a0d95e297e1c1 | ||||
| Steps To Reproduce | See source code. | ||||
| Tags | No tags attached. | ||||
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Something like this should work and showed sane performance in my initial simple test case. activePressureForceBaffleVelocityFvPatchVectorField.patch (2,444 bytes)
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
index 7060887..a4932a3 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/activePressureForceBaffleVelocity/activePressureForceBaffleVelocityFvPatchVectorField.C
@@ -240,37 +240,33 @@ void Foam::activePressureForceBaffleVelocityFvPatchVectorField::updateCoeffs()
const labelList& nbrFaceCells = nbrPatch.patch().faceCells();
scalar valueDiff = 0;
+ scalar patchArea = 0.0;
- if (fBased_)
+ // Add this side
+ forAll(cyclicFaceCells, facei)
{
- // Add this side
- forAll(cyclicFaceCells, facei)
- {
- valueDiff +=p[cyclicFaceCells[facei]]*mag(initCyclicSf_[facei]);
- }
-
- // Remove other side
- forAll(nbrFaceCells, facei)
- {
- valueDiff -=p[nbrFaceCells[facei]]*mag(initCyclicSf_[facei]);
- }
+ valueDiff +=p[cyclicFaceCells[facei]]*mag(initCyclicSf_[facei]);
+ patchArea += mag(initCyclicSf_[facei]);
+ }
+ // Remove other side
+ forAll(nbrFaceCells, facei)
+ {
+ valueDiff -=p[nbrFaceCells[facei]]*mag(initCyclicSf_[facei]);
+ }
+
+ if(fBased_)
+ {
Info<< "Force difference = " << valueDiff << endl;
}
- else // pressure based
+ else //pressure based then weighted by area
{
- forAll(cyclicFaceCells, facei)
- {
- valueDiff += p[cyclicFaceCells[facei]];
- }
+ valueDiff = valueDiff/gSum(patch().magSf());
+ Info<< "Average pressure difference = " << valueDiff << endl;
+ }
- forAll(nbrFaceCells, facei)
- {
- valueDiff -= p[nbrFaceCells[facei]];
- }
+ reduce(valueDiff, sumOp<scalar>());
- Info<< "Pressure difference = " << valueDiff << endl;
- }
if ((mag(valueDiff) > mag(minThresholdValue_)) || baffleActivated_)
{
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Resolved by https://github.com/OpenFOAM/OpenFOAM-dev/commit/f028e4f5563001171ed2fc130ba0279c23de22db |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2021-10-18 14:43 | peksa | New Issue | |
| 2021-10-18 16:03 | peksa | File Added: activePressureForceBaffleVelocityFvPatchVectorField.patch | |
| 2021-10-18 16:03 | peksa | Note Added: 0012241 | |
| 2024-07-10 16:57 | will | Assigned To | => will |
| 2024-07-10 16:57 | will | Status | new => resolved |
| 2024-07-10 16:57 | will | Resolution | open => fixed |
| 2024-07-10 16:57 | will | Fixed in Version | => dev |
| 2024-07-10 16:57 | will | Note Added: 0013311 |
