View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000134 | OpenFOAM | Bug | public | 2011-02-10 12:42 | 2012-11-05 14:29 |
| Reporter | bgschaid | Assigned To | |||
| Priority | normal | Severity | major | Reproducibility | have not tried |
| Status | closed | Resolution | no change required | ||
| Summary | 0000134: Unphysical velocity patterns at the interface of a porous zone | ||||
| Description | As described in http://www.cfd-online.com/Forums/openfoam/82729-poroussimplefoam-oscillating-velocity-porous-zone.html for low permeabilities there is an oscillation at the interface of a porous zone. Investigations show that after the pressure correction phi is correct but the ripples are introduced by U -= rUA*fvc::grad(p) (equivalent formulation for the incompressible solvers) possibly by the differences in the matrix. This can be avoided by doing the complete reconstruction U = fvc::reconstruct(phi) (divide by rho for compressible solvers) | ||||
| Tags | No tags attached. | ||||
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Using U = fvc::reconstruct(phi); causes a HUGE momentum conservation error but if momentum conservation is not important in your cases then yes it does remove spurious "wiggles" of many kinds. |
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Point taken. Should have checked that too (pressure drop and velocity profiles were alright) Anyway: for models that use U these wiggles produce "interesting" results. For instant when taking the angledDuctImplicit/rhoPorousSimpleFoam-tutorial and increasing the Darcy coefficient by two orders of magnitude one sees that each porous interface "produces" turbulence. Probably because the kEpsilon-model takes the gradient of the wiggle. Other stuff (lagrangian) might be affected, too So it is not a purly cosmetic/postprocessing problem |
