DICPCG calculation don't converge (interFoam)
 

Hello, CFD Online users.

I'm working on a 3 dimensional 2 phase flow calculation of circular tube.
Inlet BC was set for gas and liquid to flow into the tube alternately using GroovyBC. SymmetryPlane was used to calculate half part of round tube.

The calculation was done up to some time step without problem. But, at the time step just behind the Inlet BC had changed as alpha1=1 to 0, the p_rgh DICPCG iteration didn't converge.

In more detail, final residual became larger than initial residual and iteration no. reached at the upper limit of 1000. Normally, final residual converges to 10^-6 order, final residual was 0.0177 after PISO loop (nCorrectors=3). Convergence didn't improved at all after changing nCorrectors=3 to 5. As a result, alpha1max>1, Co>1 and deltaT decrease lead to calculation abort.

Previously, I worked on the same case in 2D simulation and the calculation was successfully completed with no problem.

I attached archive.zip including 0 files, system files, log and image.

I've been tacking this problem over a week but I still haven't found what was wrong.

Any advice is welcome!
Thanx :)