POLYFLOW - Flow case with full slipping and inflow (constant normal force) may fail
When defining a flow case (extrusion or not) with inflow calculation based on constant normal force and involving full slipping, the calculation may diverge.
This may also happen with prior versions of POLYFLOW.
The typical message is:
Divergence of influent solver occurred !
Warning in EVOLUT
First step does not converge
It is not possible to start the evolution scheme
A closer analysis of the listing file reveals that the calculation diverges for the variable "Grad P".
This is caused by the evaluation of the relative error on a field which actually vanishes (pressure gradient). A possible remedy consists of running the calculation with a tiny amount of friction (at least), or with a non-zero initial value of the evolution parameter S.