Temperature in simpleFoam takes lots of Iterations
 

Hey Guys,

i added temperature to simpleFoam as described in this Tutorial for icoFoam.
Everything works fine, though the Solution needs a lot of Time since the Solving for T needs about 500 Iterations, which themselves require noticeable more time than the other variables. I've waited nearly a day and it doesn't get better. Is is a large Mesh so i it would be great if anyone had any experience in whether this is preventable or maybe necessary?

The entry in fvSolution is:

T
{
solver BICCG;
preconditioner DILU;
tolerance 1e-7;
relTol 0;
};

The entries in fvSchemes are:

divSchemes
{
div(phi,T) Gauss upwind;
}

laplacianSchemes
{
default Gauss linear corrected;
}


Here an extract of the log-File:

DILUPBiCG: Solving for Ux, Initial residual = 0.00100392, Final residual = 1.55987e-06, No Iterations 3
DILUPBiCG: Solving for Uy, Initial residual = 0.000223085, Final residual = 1.98551e-06, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 0.00409009, Final residual = 2.67272e-06, No Iterations 4
DICPCG: Solving for p, Initial residual = 0.0102603, Final residual = 0.000508878, No Iterations 10
time step continuity errors : sum local = 0.00022309, global = -3.75985e-05, cumulative = -0.0631543
DILUPBiCG: Solving for omega, Initial residual = 1.34598e-05, Final residual = 1.55138e-06, No Iterations 1
bounding omega, min: -55157.8 max: 7.30739e+06 average: 74327.1
DILUPBiCG: Solving for k, Initial residual = 0.00209203, Final residual = 3.94547e-06, No Iterations 3
bounding k, min: -0.000121144 max: 1.54218 average: 0.0210219
DILUPBiCG: Solving for T, Initial residual = 0.000117996, Final residual = 9.23239e-08, No Iterations 527
ExecutionTime = 80799 s ClockTime = 80875 s

This is my first question in this Forum, so i hope everything is fine, thanks for answers!

Hi,

set "relTol" to "0.1"

Best Regards,
Christian

Thank you Chris, now it does about 300 Iterations which is already much better!

Same problem with p
 

DILUPBiCG: Solving for Ux, Initial residual = 0.239894, Final residual = 0.0179294, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.179769, Final residual = 0.0125606, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.641576, Final residual = 0.0401016, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.0565956, Final residual = 0.00545759, No Iterations 679
time step continuity errors : sum local = 10.8709, global = 0.0357859, cumulative = 1.01927
DILUPBiCG: Solving for epsilon, Initial residual = 0.100542, Final residual = 0.00703845, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 0.200465, Final residual = 0.0159354, No Iterations 1
ExecutionTime = 246.64 s ClockTime = 250 s

Please let me know how cope up with this.

Try using a multi-grid (GAMG) solver for the pressure equation, and have a look at the motorBike tutorial to get an impression on how to use it.

Meindert,

Thank you for quick reply I'll try this.