Hello Clemens,
When running for example confluence in serial mode, you have the following writing in the listing:
THERE IS 3 LIQUID BOUNDARIES:
BOUNDARY 1 :
BEGINS AT BOUNDARY POINT: 421 , WITH GLOBAL NUMBER: 1
AND COORDINATES: 0.000000 0.000000
ENDS AT BOUNDARY POINT: 429 , WITH GLOBAL NUMBER: 2370
AND COORDINATES: 0.000000 0.8000000
BOUNDARY 2 :
BEGINS AT BOUNDARY POINT: 144 , WITH GLOBAL NUMBER: 2011
AND COORDINATES: -7.371499 3.330000
ENDS AT BOUNDARY POINT: 150 , WITH GLOBAL NUMBER: 2012
AND COORDINATES: -7.981899 3.330000
BOUNDARY 3 :
BEGINS AT BOUNDARY POINT: 256 , WITH GLOBAL NUMBER: 1507
AND COORDINATES: -10.80000 0.8000000
ENDS AT BOUNDARY POINT: 264 , WITH GLOBAL NUMBER: 1508
AND COORDINATES: -10.80000 0.000000
You then have the order of every liquid boundaries and the the number of first and last node.
Boundaries are described anticlockwise.
You can do the same with your geometry with only 1 time step.
Otherwise, and more easily, you can run a postel script (e.g. for confluence example):
plot.py mesh2d geo_confluence.slf -b geo_confluence.cli --liq-bnd
Hope this helps,
Chi-Tuan