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IDProjectCategoryView StatusDate SubmittedLast Update
0004011OpenFOAMBugpublic2023-08-28 01:372023-08-28 10:22
ReporterSamMallinson Assigned Tohenry  
PrioritynormalSeveritycrashReproducibilityalways
Status closedResolutionno change required 
PlatformUnixOSUbuntuOS Version20.04
Product Version11 
Summary0004011: Ability to switch off thermophysics removed?
DescriptionIs it still possible to run CHT problems with heating switched off (to establish a steady flow field)?

Has the thermophysics flag been removed? The source code still has it at https://github.com/OpenFOAM/OpenFOAM-11/blob/e21232d6cbfe8e592af005eb229a11e996730b36/src/finiteVolume/cfdTools/general/solutionControl/solutionControl/fluidSolutionControl/fluidSolutionControl.H#L110

I cannot see it being used in the rivuletPanel tutorial, as was the case in OpenFOAM-10/tutorials/combustion/buoyantReactingFoam/Lagrangian/rivuletPanel/.

I am asking because I have used it for the "flow" part of a CHT run in foamMultiRun, but the heat equation is still being solved, and the run crashes after a few steps. NB: the case runs fine in OF-10.


This snippet shows the 1st step, which completed without issue, showing the solution for liquid:e (adding ** for emphasis)
 
```code
        Time = 1s

liquid DILUPBiCGStab: Solving for Ux, Initial residual = 1, Final residual = 0.0026653598, No Iterations 1
liquid DILUPBiCGStab: Solving for Uy, Initial residual = 1, Final residual = 0.0023560387, No Iterations 1
liquid DILUPBiCGStab: Solving for Uz, Initial residual = 1, Final residual = 0.003069454, No Iterations 1
liquid patchToPatch: Calculating couplings between 26464 source faces and 26426 target faces
liquid 52890 couplings calculated in 0.143862s
liquid patchToPatch: Calculating couplings between 45409 source faces and 45409 target faces
liquid 90818 couplings calculated in 0.266201s
**liquid DILUPBiCGStab: Solving for e, Initial residual = 0.27042415, Final residual = 0.0026841366, No Iterations 8**
plastic patchToPatch: Calculating couplings between 28676 source faces and 28676 target faces
plastic 57352 couplings calculated in 0.107232s
plastic DICPCG: Solving for e, Initial residual = 0.010159641, Final residual = 4.0432682e-09, No Iterations 10
silicon DICPCG: Solving for e, Initial residual = 0.24007365, Final residual = 4.5386237e-09, No Iterations 12
liquid GAMG: Solving for p_rgh, Initial residual = 1, Final residual = 0.0022960011, No Iterations 2
liquid GAMG: Solving for p_rgh, Initial residual = 0.85696682, Final residual = 0.0082115491, No Iterations 2
liquid GAMG: Solving for p_rgh, Initial residual = 0.18312201, Final residual = 0.0013543687, No Iterations 4
liquid GAMG: Solving for p_rgh, Initial residual = 0.048399865, Final residual = 0.0002669282, No Iterations 4
liquid time step continuity errors : sum local = 0.0012302444, global = -0.0004800804, cumulative = -0.0004800804
        ExecutionTime = 2.459131 s ClockTime = 2 s
```

Similar result for step 2 (except that the liquid:e solution encounters a singularity)

For step 3, the solution of liquid:e throws up ridiculous values for T:

```code
        Time = 3s

liquid DILUPBiCGStab: Solving for Ux, Initial residual = 0.16684387, Final residual = 0.00017814001, No Iterations 1
liquid DILUPBiCGStab: Solving for Uy, Initial residual = 0.16441381, Final residual = 0.00022412894, No Iterations 1
liquid DILUPBiCGStab: Solving for Uz, Initial residual = 0.17026317, Final residual = 0.00016461383, No Iterations 1
liquid DILUPBiCGStab: Solving for e, Initial residual = 0.99899064, Final residual = 6.0116102e+31, No Iterations 1000
            [3] iter Test e/h Cv/p Tnew
            [3] 0 300.00985 7.7778817e+09 4.182e+09 -7.223968e+16
            [3] 1 -7.223968e+16 -3.0210634e+26 4.182e+09 -7.223968e+16
            [3] 2 -7.223968e+16 -3.0210634e+26 4.182e+09 -7.223968e+16
            [3] 3 -7.223968e+16 -3.0210634e+26 4.182e+09 -7.223968e+16
....
```

This is despite having the following entry in system/liquid/fvSolution

```code
PIMPLE
{
    thermophysics false;
```

Steps To ReproduceDownload and unzip file cht_of11.tar
Issue foam bash command (ie 'source /path/to/OpenFOAM-11/etc/bashrc')
./Allrun

NB: requires Gmsh and Python3
Additional InformationAlso attached .tar of case files for OF-10
TagsNo tags attached.

Activities

SamMallinson

2023-08-28 01:37

reporter  

cht_of11.tar (194,560 bytes)
cht_of10.tar (194,560 bytes)

henry

2023-08-28 09:24

manager   ~0013105

With the modular solvers you can choose a solver which does not include the energy equation rather one that does and then switch it off.

henry

2023-08-28 10:21

manager   ~0013106

Note also that in foamMultiRun you can optionally specify the number of energy correctors to loop over the multi-region coupled energy equations and you can set this number to 0 if you do not want to solve the energy system at all, e.g. in tutorials/multiRegion/CHT/coolingCylinder2D/system/fvSolution:

PIMPLE
{
    nOuterCorrectors 1;
    nEnergyCorrectors 0;
}

henry

2023-08-28 10:22

manager   ~0013107

User support request.

Issue History

Date Modified Username Field Change
2023-08-28 01:37 SamMallinson New Issue
2023-08-28 01:37 SamMallinson File Added: cht_of11.tar
2023-08-28 01:37 SamMallinson File Added: cht_of10.tar
2023-08-28 09:24 henry Note Added: 0013105
2023-08-28 10:21 henry Note Added: 0013106
2023-08-28 10:22 henry Assigned To => henry
2023-08-28 10:22 henry Status new => closed
2023-08-28 10:22 henry Resolution open => no change required
2023-08-28 10:22 henry Note Added: 0013107