The Continuity node, exists as an option at interfaces between parts in an assembly, from the Pairs submenu. The condition is similar to the Material Discontinuity condition that applies to interior boundaries. The difference is that the Continuity condition should also be applied both when the same material exists on the two sides of a pair and when the material is different. The advantage of using a pair feature is that the mesh does not need to be conforming on the two sides of the interface (the two parts of the assembly). This is especially advantageous for the time explicit discontinuous Galerkin method as the time step depends on mesh size and local speed of sound.

The time-explicit DG-FEM method uses an efficient quadrature free computation of the boundary flux. This can in certain cases result in unstable behavior when pair conditions are used with non-conforming meshes. To remedy this a more accurate projection based quadrature method is used (per default) on all pair conditions, such as the Continuity condition.

Click to select Use a projection based quadrature method for the boundary flux computation (selected per default).