+ If you use \b several hypotheses to define viscous layers on faces of
+ one solid, keep in mind the following. Each hypothesis defines a set
+ of faces with viscous layers (even if you specify faces without
+ layers). The sets of faces with viscous layers defined by several
+ hypotheses should not intersect, else the module won't add an
+ hypothesis that is incompatible with another one. <br>
+ Also you can't define different number of layers on adjacent faces
+ of a solid.<br>
+ This logic is also valid for the 2D hypothesis.