about the phase field output

[swh2011]

Dear Bernd:
I met a problem in the simulation of the solidification of some multi-component Al alloys. The korn output (shown in the circle of fig 3) indicates it is an intermetallics phase. The concentration outputs also show it is an intermetallics phase. But the phase field output(shown in the circle of fig 2) shows it is an interface. But for other grains of intermetallics phase, the phase field output is consistent with the korn output as well as concentration output. The simulation domain is 200*200, dx=1micrometers, phase minimum 5E-4, interface thickness 5 cells. I have changed phase minimum to 1E-8, it seems there is no significant improvement. If the simulation continue and grains grow further, the phase phase field will still not turn to intermetallics index.

Thank you very much.
Best wishes.
swh

[Bernd]

Dear swh,

The difference in the two outputs is that - by default - the .korn output (grain number output) does not show interface regions while the .phas output (phase number output) does. That means that the .korn output always displays the grain number of the grain with the highest fraction, while the .phas output shows the phase number of grains with a fraction above 80%. All other regions are marked as interface with value -1. You can change the default behaviour of the .phas output by using the optional second parameter "no_interfaces", then it behaves like the .korn output!

For your simulation it means that, as it seems, the fraction of the intermetallic grains never exceed a value of 0.8, otherwise they would show up in the default .phas output! You should check the .frac? output to see the exact local fraction of the intermetallic phases. Probably, the fact that some of the intermetallics don't reach full fraction is due to the low resolution of the simulation...

Bernd