CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

negative initial temperature/ exceeded number of max. iteratons

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 12, 2020, 12:37
Default negative initial temperature/ exceeded number of max. iteratons
  #1
New Member
 
Join Date: Jan 2020
Posts: 13
Rep Power: 2
PSander is on a distinguished road
Hey,
I try to calculate heat transfer between a fluid in a pipe (water) and the encircling pipe and soil, using OF6 and the chtMultiRegionFoam solver for a steady state calculation.
The model crashes with the fatal error of exceede Maximum number of iterations as well the Courant-number drops below 0, what I consider as part of the problem.


Code:
Region: fluid Courant Number mean: -0.0910146934732 max: -0.00351789034512
Region: pipewall Diffusion Number mean: 2.67864717358e-06 max: 0.000233164935363
Region: soil_1 Diffusion Number mean: 5.82937716003e-06 max: 7.56997601431e-05
deltaT = 4.68264248705
Time = 10


Solving for fluid region fluid
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.929863015554, Final residual = 1.9550289574, No Iterations 1000
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.978339899353, Final residual = 1.05520532405, No Iterations 1000
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.999766111841, Final residual = 8.79009066096e-05, No Iterations 1000
DILUPBiCGStab:  Solving for e, Initial residual = 1, Final residual = 1386552.30948, No Iterations 1000


--> FOAM FATAL ERROR: 
Maximum number of iterations exceeded: 100

I read in the forum to check the mesh but I could not find any error.


If I try the same model with Euler instead of steady state, it crashes with a negative initial temperature and a extrem high courant-number (I fixed maxCo to 1 in controlDict, but it seems to be ignored).


Code:
Region: fluid Courant Number mean: 28.0700323842 max: 3023.8583768
Region: pipewall Diffusion Number mean: 9.88492992534e-05 max: 0.00860441445906
Region: soil_1 Diffusion Number mean: 2.15119726494e-05 max: 0.000279352514867
deltaT = 5.92803286081e-06
Time = 388.886


Solving for fluid region fluid
diagonal:  Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0861844749054, Final residual = 3.10312044775e-07, No Iterations 2
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.215185941109, Final residual = 1.92800159784e-07, No Iterations 2
DILUPBiCGStab:  Solving for Uz, Initial residual = 0.0288023464831, Final residual = 1.83257387023e-08, No Iterations 2
DILUPBiCGStab:  Solving for e, Initial residual = 0.256558566591, Final residual = 8.40025755292e-07, No Iterations 2


--> FOAM FATAL ERROR: 
Negative initial temperature T0: -845.998590083
In another attempt I already reduced my mesh to an easier version with only one solid part, but I get still the same probelm with negative initial temperatures or exceeded number of iterations.

Given that my model had none of those problems in OF7, I believe that the boundary conditions should be fine, so I dont know how to fix this issue.
Do you have some hint how to solve it?
Attached Files
File Type: txt blockMeshDict.txt (22.2 KB, 4 views)
File Type: txt controlDict.txt (2.4 KB, 1 views)
PSander is offline   Reply With Quote

Reply

Tags
chtmultiregionfoam, courant number, iterations exceeded, negative initial temp

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Converging Diverging Nozzle with dbnsTurbFoam Saleh Abuhanieh OpenFOAM Running, Solving & CFD 4 December 13, 2019 10:26
y+ and u+ values with low-Re RANS turbulence models: utility + testcase florian_krause OpenFOAM 113 June 25, 2019 00:58
Segmentation fault when using reactingFOAM for Fluids Tommy Floessner OpenFOAM Running, Solving & CFD 4 April 22, 2018 12:30
SigFpe when running ANY application in parallel Pj. OpenFOAM Running, Solving & CFD 3 April 23, 2015 14:53
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 06:20


All times are GMT -4. The time now is 15:28.