# bubbly flow printStack error

• Hello, everyone.
I used an interfoam based in-house codes to simulate a bubbly flow in viscoelastic fluids and there exist problems.

[43] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
[43] #1  Foam::sigFpe::sigHandler(int) at ??:?
[43] #3  ? in "/lib64/libm.so.6"
[43] #4  ? in "/lib64/libm.so.6"
[43] #5  ? in "/lib64/libm.so.6"
_pmiu_daemon(SIGCHLD): [NID 00688] [c3-0c1s12n0] [Wed Jul  3 15:17:38 2019] PE RANK 43 exit signal Floating point exception
[NID 00688] 2019-07-03 15:17:38 Apid 8681020: initiated application termination



After several steps, a Printstack error occured.
the following is the 8th time step

PIMPLE: not converged within 200 iterations
ExecutionTime = 650.72 s  ClockTime = 652 s

Courant Number mean: 0.00630634 max: 1.15664
Interface Courant Number mean: 2.01355e-05 max: 0.653551
deltaT = 5.66511e-08
Time = 1.93407e-06


Actually, the last iteration did not converge yet i did not know the exact problem.
Does anyone have hints for me?
ps: i can not upload my log file. it is too big
([0_1562165090181_3mmXanthan.e2539383](正在上传 100%) 链接地址)

• @qingdong_wang

Its hard to tell. What I see is your Courant number = 1.1, using smaller time step should be helpful. But I am not sure.

• i think i have defined max Co number as 0.4, i will check it again.
besides the delta T is quite small, right?

In addition, could you explain what is the problem in the first part code. printStake error? i have searched in cfd-online. According to it, the problem may be dividing by zero.

Thanks a lot.

• According to it, the problem may be dividing by zero

Not all the time. If your test case blows up due to dividing by zero, you will find

Foam::error::divide()....


printStake error?

It does not mean anything. If your test case blows up, you can find such information.

U need to debug further.

• okay, thanks a lot.
i will try it again.

• [2] [1] ##00    [38] #0  Foam::error::printStack(Foam::Ostream&)Foam::error::printStack(Foam::Ostream&)Foam::error::printStack(Foam::Ostream&) at ??:?
[38] #1  Foam::sigFpe::sigHandler(int) at  at ??:???:?

[1] [2] ##11    Foam::sigFpe::sigHandler(int)Foam::sigFpe::sigHandler(int) at ??:?
[38] #2  ? at ??:?
[2] #2  ? at ??:?
[1] #3  ? in "/lib64/libm.so.6"
[38] #4  ? in "/lib64/libm.so.6"
[2] #4  ? in "/lib64/libm.so.6"
[1] #4  ? in "/lib64/libm.so.6"
[38] #5  ? in "/lib64/libm.so.6"
[2] #5  ? in "/lib64/libm.so.6"
[1] #5  ? in "/lib64/libm.so.6"
in "/lib64/libm.so.6"
in "/lib64/libm.so.6"
_pmiu_daemon(SIGCHLD): [NID 00126] [c0-0c1s15n2] [Tue Jul  9 10:43:27 2019] PE RANK 38 exit signal Floating point exception
_pmiu_daemon(SIGCHLD): [NID 00082] [c0-0c1s4n2] [Tue Jul  9 10:43:27 2019] PE RANK 1 exit signal Floating point exception
[NID 00126] 2019-07-09 10:43:27 Apid 8697814: initiated application termination


I have tried it again, the same problem occurs.
Last time i have used shear gradient boundary, and this time i just use zeroGraident. However, ....

I guess. the problem is the signal floating exception???

Tks