Hi,
You may have not selected the geometric entity level correctly for the variable u. You need to create two variables node, with each variable having relevant geometric entity level.
Or another problem could be that 'u' is the name of a dependent variable, I mean 'u' could be defined as x displacement or pressure or concentration or whatever by default by COMSOL. Try renaming u.
Suresh
You may have not selected the geometric entity level correctly for the variable u. You need to create two variables node, with each variable having relevant geometric entity level.
Or another problem could be that 'u' is the name of a dependent variable, I mean 'u' could be defined as x displacement or pressure or concentration or whatever by default by COMSOL. Try renaming u.
Suresh
