View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0004261 | OpenFOAM | Bug | public | 2025-08-07 08:54 | 2025-08-08 13:45 |
| Reporter | tobias2 | Assigned To | henry | ||
| Priority | normal | Severity | major | Reproducibility | always |
| Status | closed | Resolution | no change required | ||
| Platform | GNU/Linux | OS | Other | OS Version | (please specify) |
| Product Version | 13 | ||||
| Summary | 0004261: Wrong residual calculation for zone-wise defined solid material properties | ||||
| Description | With a multi-region CHT case a zone-wise definition of solid material properties in physicalProperties delivers a wrong residuals for this region. As the calculated valuesare very low, the tolerance in fvSolution/solvers has no effect and the region will never be calculated. example form the log-file for the first itme-step, where the inital residual should be 1: solid1 DICPCG: Solving for e, Initial residual = 5.4645654e-07, Final residual = 5.4645654e-07, No Iterations 0 with fvSolution: solvers { "(h|e)" { solver PCG; preconditioner DIC; tolerance 1e-06; relTol 0.01; } } no calculation will be executed for solid1 Workaround: setting the tolerance, relTol very low or minIter. e.g. for physicalProperties: thermoType constSolidThermo; rho { type zonal; value 7850; zones { iron 7850; copper 8940; alu 2700; } } Cv { type zonal; value 750; zones { iron 450; copper 385; alu 900; } } kappa { type zonal; value 4; zones { iron 50; copper 380; alu 200; } } | ||||
| Tags | No tags attached. | ||||
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It is not clear in what way the residuals for a region would be wrong, the residuals are calculated directly from the matrix, for the residuals to be wrong the matrix would have to be wrong. We will need a small test-case which reproduces the problem, without a case we cannot reproduce it. |
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Attatched you find a testcase with a fluid region and two solid regions that are next to the fluid region. The region solid2 contains 3 zones with different material properties. The energy equation of solid2 is never solved as the inital residual of the first timestep is lower than the tolerance in solid2/fvSolution. When the tolerance is tightned the equation will be solved. |
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This all looks correct, you need to tighten the tolerance for the equation to solve. |
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You can also set minIter to e.g. 1, to have the matrix-vector equation at least once iterated through by the solver. We often set minIter 1 in our simulations since our initial matrix solver residual is voften ery small as well. |
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But does the tolerance setting in fvSolution work as intendet when it is not guaranteed that the inital residual for the first timestep is 1? I find it a bit hard to choose a appropriate tolerance and minIter setting, when there is no guarantee about the absolute residual values. |
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The residual is normalise with respect to the matrix not the initial condition. |
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User support request. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2025-08-07 08:54 | tobias2 | New Issue | |
| 2025-08-07 09:22 | henry | Note Added: 0013636 | |
| 2025-08-07 13:54 | tobias2 | Note Added: 0013638 | |
| 2025-08-07 13:54 | tobias2 | File Added: zonalHeatConductivityResiduals.zip | |
| 2025-08-07 14:17 | henry | Note Added: 0013639 | |
| 2025-08-07 18:21 | cgoessni | Note Added: 0013640 | |
| 2025-08-08 13:29 | tobias2 | Note Added: 0013642 | |
| 2025-08-08 13:45 | henry | Note Added: 0013643 | |
| 2025-08-08 13:45 | henry | Assigned To | => henry |
| 2025-08-08 13:45 | henry | Status | new => closed |
| 2025-08-08 13:45 | henry | Resolution | open => no change required |
| 2025-08-08 13:45 | henry | Note Added: 0013644 |
