View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0002936 | OpenFOAM | Bug | public | 2018-05-15 14:33 | 2018-05-15 16:41 |
| Reporter | zhernadi | Assigned To | chris | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Platform | Unix | OS | Other | OS Version | (please specify) |
| Summary | 0002936: patchAverage does not perform area weighted average | ||||
| Description | Previous OpenFOAM versions up to 3.x used patchAverage application to calculate face area weighted average of volume fields on a boundary patch. Now, in OpenFOAM 5.x, patchAverage U outlet # OpenFOAM 3.x is substituted by postProcess -func 'patchAverage(name=outlet,U)' # OpenFOAM 5.x However they do not provide the same result if the boundary patch consists of non-uniform sized faces. While 3.x version calculates face area weighted average, 5.x version simply performs ensemble averaging (sums up the face values and divides with number of faces). In most of the cases, ensemble average of volume fields does not have a physical meaning, while face area weighted average is usually meaningful. For example in simpleFoam tutorial pitzDaily, user might want to calculate mean velocity on the outlet. For the non-uniform mesh provided in pitzDaily case, face area weighted averaging should be performed to correctly calculate mean velocity. So it would be better to perform face area weighted averaging in patchAverage for two reasons: 1. backward compatibility with OpenFOAM 3.x or older 2. higher chance for physically meaningful results | ||||
| Steps To Reproduce | # In OpenFOAM 5.x: cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/pitzDaily /tmp/pitzDaily5x cd /tmp/pitzDaily5x blockMesh > log.blockMesh simpleFoam > log.simpleFoam postProcess -func 'patchAverage(name=outlet, U)' # In OpenFOAM 3.x: cp -r $FOAM_TUTORIALS/incompressible/simpleFoam/pitzDaily /tmp/pitzDaily3x cd /tmp/pitzDaily3x blockMesh > log.blockMesh simpleFoam > log.simpleFoam patchAverage U outlet # Physically correct value is provided by OpenFOAM 3.x | ||||
| Additional Information | This issue could be easily solved by modifying the file $FOAM_ETC/caseDicts/postProcessing/surfaceFieldValue/patchAverage Change the line operation average; to operation areaAverage; | ||||
| Tags | No tags attached. | ||||
|
|
Thanks for the report. Resolved in dev: https://github.com/OpenFOAM/OpenFOAM-dev/commit/c7d711 Resolved in 5.x: https://github.com/OpenFOAM/OpenFOAM-5.x/commit/d06c3b |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2018-05-15 14:33 | zhernadi | New Issue | |
| 2018-05-15 16:41 | chris | Note Added: 0009579 | |
| 2018-05-15 16:41 | chris | Assigned To | => chris |
| 2018-05-15 16:41 | chris | Status | new => resolved |
| 2018-05-15 16:41 | chris | Resolution | open => fixed |
| 2018-05-15 16:41 | chris | Status | resolved => closed |
