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-   -   ShockTube, error message. (http://www.cfd-online.com/Forums/openfoam/94457-shocktube-error-message.html)

foamer November 16, 2011 12:04

ShockTube, error message.
 
Hi

i am investigating a case by using the shockTube tutorial, (rhoCentralFoam solver).

My problem is that i get an error message when i am running the simulation. the simulation starts to run, but after a short time i receive an error message. the problem is that i do not know what it means.

An excerpt of the two last iterations and the error message i receive is:


diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 0.12 s ClockTime = 1 s

Mean and max Courant Numbers = 0.0993913 0.2
deltaT = 1e-05
Time = 0.0001

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoUx, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
ExecutionTime = 0.13 s ClockTime = 1 s

#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 in "/lib/libc.so.6"
#3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) in "/opt/openfoam171/lib/linux64GccDPOpt/libOpenFOAM.so"
#4
in "/opt/openfoam171/applications/bin/linux64GccDPOpt/rhoCentralFoam"
#5
in "/opt/openfoam171/applications/bin/linux64GccDPOpt/rhoCentralFoam"
#6 __libc_start_main in "/lib/libc.so.6"
#7
in "/opt/openfoam171/applications/bin/linux64GccDPOpt/rhoCentralFoam"
Floating point exception


I have a fealing that the errouniosity is based on the changes i did to the setFieldsDict file. My setFieldsDict file looks like:

defaultFieldValues ( volVectorFieldValue U ( -1000 0 0 ) volScalarFieldValue T 349 volScalarFieldValue p 100000 );

regions ( boxToCell { box ( 0 -1 -1 ) ( 5 1 1 ) ; fieldValues (volVectorFieldValue U ( 1000 0 0 ) volScalarFieldValue T 349 volScalarFieldValue p 100000 ) ; } );


i will have deeply appreciated if someone could have explained to me what the error message means and what i can do to cope with this problem.

Alex

foamer November 17, 2011 06:37

Hi

I think i know what is the problem.
When i check the pressure in time folder 0.001 i eventually get negative pressure. So i guess this has to do with the numerics in the algorithm or so, that it cannot handle it.


Alex

Farshad_Noravesh December 1, 2012 03:13

zero residuals
 
Hi,

Did you solve the problem? I am still getting your error. Even when i use other tutorials of rhoCentralFoam i still get the same error.

please help me.

Kind Regards,

Farshad

foamer December 1, 2012 16:22

Quote:

Originally Posted by Farshad_Noravesh (Post 395124)
Hi,

Did you solve the problem? I am still getting your error. Even when i use other tutorials of rhoCentralFoam i still get the same error.

please help me.

Kind Regards,

Farshad



Farshad, i think the velocity is too high...if you lower the velocity to 900 m/s it should be able to run...

Hope this will work for you :)



alex

immortality December 2, 2012 18:02

may be the problem is from turbulency

foamer December 3, 2012 08:37

Quote:

Originally Posted by immortality (Post 395328)
may be the problem is from turbulency


Ok, could you please specify that a little more ?


alex

immortality December 4, 2012 13:24

I have the same problem.it seems the equations of rho don't solve at all.because rho,rhoUx,rhoUy,rhoUz and rhoe are zero in my run.
I don't whats the cause of the problem.

praveen December 10, 2012 12:44

Try reducing cfl number and/or time step.

vwibaut January 30, 2013 05:31

Hi all,

I'm solving the flow in a nozzle and I have the same problem that foamer
Quote:

My problem is that i get an error message when i am running the simulation. the simulation starts to run, but after a short time i receive an error message. the problem is that i do not know what it means.
Just reducing the velocity solves your problem?

Regards


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