The Continuity condition is suitable for pairs where the boundaries match; it prescribes that the volume fraction for each phase is continuous across the pair.

A No Flux subnode is added by default and it applies to the parts of the pair boundaries where a source boundary lacks a corresponding destination boundary and vice versa. The No Flux feature can be overridden by any other boundary condition that applies to exterior boundaries. By right-clicking the Continuity node, additional fallback feature subnodes can be added.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog. The Constraints settings can be set to Use pointwise constraints (default) or to Use DG constraints (if possible). This latter option uses DG constraints as long as the selected boundaries are not adjacent to a porous domain. If the boundary selection contains boundaries adjacent to a porous domain, pointwise constraints are used instead. DG constraints are recommended on pairs adjacent to a Fluid feature, especially when the mesh vertices do not match across the pair or when the mesh is sliding.