Reply To: Low Re flow inside Microchannel
As I wrote above the the assertion error is due to an invalid value for normalTemp which in turn is caused by a cell of material 1 being surrounded by material 5 (boundary) in such a way that the normal directions cancel (but counter is still non-zero s.t. the following code is wrongly called).
I’d suggest to take a closer look at your material geometry and e.g. to increase the resolution to prevent such degenerate fluid cells. Additionally (or alternatively) you can add a non-zero check to the conditional in line 79.
The normalization on its own is necessary to fullfill the preconditions of STL distance calculation in line 95.