CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (http://www.cfd-online.com/Forums/openfoam-solving/)
-   -   time step continuity error (http://www.cfd-online.com/Forums/openfoam-solving/95317-time-step-continuity-error.html)

rosh December 13, 2011 11:10

time step continuity error
 
hi everyone,

I recently started to work with OP, so I have created a case as a cube which has inlet, outlet and walls.... I use icoFoam. Under /0/ directory I have p and U files. I created my mesh, but when I want to run the icoFoam I get the following error for time step continuity:
---------------------------------------------------------------------------------------------

Create time

Create mesh for time = 0

Reading transportProperties

Reading field p

Reading field U

Reading/calculating face flux field phi


Starting time loop

Time = 0.001

Courant Number mean: 2.5e-05 max: 0.005
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 1.37371e-06, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG: Solving for p, Initial residual = 1, Final residual = 9.12929e-07, No Iterations 100
time step continuity errors : sum local = 4.56464e-11, global = 8.537e-14, cumulative = 8.537e-14
DICPCG: Solving for p, Initial residual = 0.000597641, Final residual = 9.14417e-07, No Iterations 73
time step continuity errors : sum local = 1.99697e-08, global = 2.57976e-10, cumulative = 2.58061e-10
ExecutionTime = 0.15 s ClockTime = 0 s

Time = 0.002

Courant Number mean: 0.0100006 max: 0.0100859
DILUPBiCG: Solving for Ux, Initial residual = 0.991413, Final residual = 2.94309e-07, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 0.352816, Final residual = 2.70294e-07, No Iterations 2
DICPCG: Solving for p, Initial residual = 0.00283373, Final residual = 8.46871e-07, No Iterations 81
time step continuity errors : sum local = 1.49667e-08, global = -1.2039e-10, cumulative = 1.37671e-10
DICPCG: Solving for p, Initial residual = 0.00322282, Final residual = 8.57637e-07, No Iterations 80
time step continuity errors : sum local = 3.41541e-09, global = -4.48079e-12, cumulative = 1.33191e-10
ExecutionTime = 0.2 s ClockTime = 0 s



so I don't know exactly where is my mistake... it would be nice if someone can help me to find my mistake,
Thanks
Rosh

Bandfrosch December 14, 2011 18:52

hi Rosh,
there is no mistake , your log looks good.
The lines
time step continuity errors : sum local = 3.41541e-09, global = -4.48079e-12, cumulative = 1.33191e-10
are numerical error estimations . Your values are small.

Keep foaming ...

Bandfrosch


All times are GMT -4. The time now is 11:14.