Hi there

I am doing studies on flow in an axisymmetric cylinder with a microchannel vertical gap. When the microchannel gap is modelled less than 20 microns (with laminar solver) a message appears "DIVERGENCE DETECTED IN AMG SOLVER - TEMPERATURE". I turned off the energy equation, reduced the relaxation factors (then the message appears as divergence in pressure correction solver). I even tried different solvers from laminar to turbulent but this makes things worse. None of these problems occur with microchannel sizes of 20 microns or more.

Any suggestions would be of great help...

Many thanks in advance... Andrew C

Apologies... wrong name for title of setting up animations - should be divergence problems....

Hi Andrew,

I have had similar problems when I am running too coarse a mesh or if I have a random connector floating in space.

I would check the mass imbalance and visualise it to see where it is. This might point you towards the position of this error. Also, check pressure and velocity distributions to see if they look correct-ish. It may be as simple as a boundary condition setup wrong, which visualising will show instantly.

Also, make sure that your mesh is refined very well around the 20 Micron area...

Regards, Scott