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May 22, 2020, 09:37 

#21 
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Join Date: Aug 2016
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This error is caused when the solver tries to find T from h (or another energy variable). The task is to find T from known h when h = cp(T) * T and this is solved by a simple Newtonapproach.
T is estimated and then recalculated until convergence is reached. Bad estimates can lead to negative temperatures and cause the error. It's not always easy to find out why the estimated T is bad, but some possible reasons have been mentioned previously:  bad mesh  bad interpolation schemes  bad thermophysical properties 

July 24, 2020, 22:03 
the same problem in rhoCentralFoam and rhoPimpleFoam solvers.

#22 
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Rebel Young
Join Date: Jul 2020
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It occurred in rhoC and rhoP solvers.
The temperature limiter in fvOption does not work, because I add the minMax functions in controlDict. The minimum temperature in the fields is not negative. In my case , the error happened after about 30100 time steps. So the negative initial temperature is in the subiteration. I can not find a solution so far... 

July 24, 2020, 22:39 

#23  
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Rebel Young
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Quote:
As your advice, in rhoCentralFoam solver, it solves rho and rhoE for estimating the temperature, which has the equation "e=cv*T" . For the normalized gas , the Cv is constant. So the negative initial temperature means the energy is negative? 

October 17, 2020, 02:23 

#24 
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Niko_choko
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Can confirm that changing mesh did work for me too.


October 28, 2020, 15:21 

#25 
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Jonathan Wells
Join Date: Oct 2020
Location: Indiana
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I am having the same issue, but I don't have a mesh problem. My entire domain is uniform spacing in a rectangular grid, so there is no change in mesh size, aspect ratio, or skewness. The solution runs fine with coarser grids, but my current grid is in no way overrefined, as edge length is 1 mm. I am doing LES in rhoPimpleFoam.


October 28, 2020, 19:11 

#26 
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Jonathan Wells
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Location: Indiana
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As a followup, I noticed that for my grid the max Courant number was approaching 1 when I would get the error. I reduced the dt and solved my issue.


November 19, 2020, 04:55 

#27 
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Bineet Mehra
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February 4, 2021, 03:34 
same problem in chtMultiRegionFoam

#28 
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Said CATALBAS
Join Date: Feb 2020
Location: Türkiye
Posts: 55
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Hi,
I'm having same problem in LES, I tried with refined mesh but the result is the same again. Also when i added temperature limit in fvOption it stops iterrate after like 200 iterates. Maybe the problem is in my boundary conditions. I'm open any suggestion. Files attached. Kind regards Said. checkMesh Code:
Create time Create polyMesh for time = 0 Time = 0 Mesh stats points: 34125 faces: 386106 internal faces: 380986 cells: 191773 faces per cell: 4 boundary patches: 3 point zones: 0 face zones: 0 cell zones: 2 Overall number of cells of each type: hexahedra: 0 prisms: 0 wedges: 0 pyramids: 0 tet wedges: 0 tetrahedra: 191773 polyhedra: 0 Checking topology... Boundary definition OK. Cell to face addressing OK. Point usage OK. Upper triangular ordering OK. Face vertices OK. Number of regions: 1 (OK). Checking patch topology for multiply connected surfaces... Patch Faces Points Surface topology inlet 214 128 ok (nonclosed singly connected) outlet 242 142 ok (nonclosed singly connected) wall 4664 2372 ok (nonclosed singly connected) Checking geometry... Overall domain bounding box (0.025 0.125 0.025) (0.025 0.125 0.025) Mesh has 3 geometric (nonempty/wedge) directions (1 1 1) Mesh has 3 solution (nonempty) directions (1 1 1) Boundary openness (8.44415e17 7.50933e17 5.0822e18) OK. Max cell openness = 2.41502e16 OK. Max aspect ratio = 5.2589 OK. Minimum face area = 1.47893e07. Maximum face area = 3.61292e05. Face area magnitudes OK. Min volume = 2.65313e11. Max volume = 6.60658e08. Total volume = 0.000625. Cell volumes OK. Mesh nonorthogonality Max: 53.9367 average: 14.5269 Nonorthogonality check OK. Face pyramids OK. Max skewness = 0.518146 OK. Coupled point location match (average 0) OK. Mesh OK. End 

February 7, 2022, 09:23 

#29 
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Joao Coelho
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February 19, 2022, 07:25 

#30 
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ZhuangLi
Join Date: Jan 2022
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Hi Tobias,
I got into trouble with the negative temperature, could you give me some advice to deal with it? Thanks in advance! _______ Kind regards! Zhuangli 

February 20, 2022, 12:32 

#31  
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Mahdi
Join Date: Jul 2012
Posts: 53
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Quote:
fvOptions limitTemperature crashing in compressibleInterFoam 

February 20, 2022, 19:42 

#32  
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ZhuangLi
Join Date: Jan 2022
Posts: 13
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Quote:


August 3, 2022, 05:12 
How to trace back from 'negative initial temperature T0'

#33 
New Member

I ran buoyantSimpleFoam with Boussinesq as the EoS but it crashed at Time=3 for ‘negative initial temperature T0=24’ error. fvOptions limitT solves it, but the resulting flow pattern is unphysical. I would like to trace back in the code to find out what causes T0 < 0 (T0 is given as a fixed number in the EquationOfState subdict in constant/thermophysicalProperties as one of the requisite parameters for the Boussinesq EoS.)
My question: How to trace back from the thermol.H at line 300 (grep r 'Negative initial temperature T0' reports it as the only place where this text appears under src/) through the source codes? thermol.H is at https://cpp.openfoam.org/v9/thermoI_8H_source.html td p { orphans: 0; widows: 0; background: transparent }p { lineheight: 115%; marginbottom: 0.1in; background: transparent } 

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chtmultiregionsimpefoam, temperature calculation 
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