This node can be added to pairs. It prescribes that the moisture content is continuous across the pair. Continuity is only suitable for pairs where the boundaries match. Depending on the domain conditions active in the adjacent domains, the constraint is applied either on relative humidity, vapor concentration or vapor mass fraction on boundary pairs. For continuous temperature and pressure conditions, all these constraints are equivalent.

Choose the pair on which to apply this condition. A pair has to be created first. See Identity and Contact Pairs in the COMSOL Multiphysics Reference Manual for more details.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box.

The Constraint settings can be set to Nitsche constraints (default), Pointwise constraints or Weak constraints. The Nitsche constraints option ensures continuity of the diffusive flux. This option may work better than the Pointwise constraints or Weak constraints when the meshes of the source and destination boundaries do not coincide. Alternatively, select the Pointwise constraints option. Select Weak constraints to replace the standard constraints with a weak implementation.

Select the Disconnect pair check box to disable the continuity condition.

Physics Tab with interface as Moisture Transport in Air, Moisture Transport in Building Materials, or Moisture Transport in Porous Media selected: