solution singularity

February 20, 2007, 19:28

Hi

Could some one please tell me, why I am getting following message while I simulate a 3D simple domain with simpleFoam solver. Is it due to the improper boundary condition definition?

BICCG: Solving for Ux: solution singularity
BICCG: Solving for Uy: solution singularity
BICCG: Solving for Uz: solution singularity
ICCG: Solving for p: solution singularity
time step continuity errors : sum local = nan, global = nan, cumulative = nan
BICCG: Solving for epsilon: solution singularity
BICCG: Solving for k: solution singularity

-Liton

hjasak · February 21, 2007, 02:32

Yes: you have probably messed up the boundary conditions, e.g. specified both the pressure and velocity on the same patch. Other possibilities are things like using zero viscosity and central differencing on convection, not under-relaxing the equations or similar.

As a result, your solver is doing division by zero or a similar error. If you want to stop producing NaN-s or maybe even find out precisely how it fails, try:

setenv FOAM_SIGFPE 1

Hrv

February 20, 2007, 19:28	Hi Could some one please t	#1
litonx Guest Posts: n/a	Hi Could some one please tell me, why I am getting following message while I simulate a 3D simple domain with simpleFoam solver. Is it due to the improper boundary condition definition? BICCG: Solving for Ux: solution singularity BICCG: Solving for Uy: solution singularity BICCG: Solving for Uz: solution singularity ICCG: Solving for p: solution singularity time step continuity errors : sum local = nan, global = nan, cumulative = nan BICCG: Solving for epsilon: solution singularity BICCG: Solving for k: solution singularity -Liton

February 21, 2007, 02:32	Yes: you have probably messed	#2
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,907 Rep Power: 33	Yes: you have probably messed up the boundary conditions, e.g. specified both the pressure and velocity on the same patch. Other possibilities are things like using zero viscosity and central differencing on convection, not under-relaxing the equations or similar. As a result, your solver is doing division by zero or a similar error. If you want to stop producing NaN-s or maybe even find out precisely how it fails, try: setenv FOAM_SIGFPE 1 Hrv Kummi and kcavatar like this. __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

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