Calculating Shapefactor of a isotropical corner

Hello.

I am relatively new with COMSOL and is thereby not that good with the different tools and methods in,
which to find out different values etc.

Currently am I trying to find out a shapefactor of a 90deg solid corner, but can not currently figure out
how to get started.

My 2D-corner consist of one material with isotropical properties. The walls is 0,1m wide and 0,5m long.

Can anybody help me?

bg.
Rasmus Nielsen