Flux/Source

The boundary condition can be used on exterior boundaries only. With this node, the boundary condition is enforced according to:

where g and q can be specified. Here the dependent variable u in the right-hand side is evaluated on the inside (as seen from the domain where the PDE interface is defined). When the normal vector is used in expressions for curved boundaries, it is important that the mesh version of these vectors is used. The components of this vector are denoted nxmesh, nymesh, and nzmesh, respectively.


	In this context, exterior means exterior to the PDE interface, which does not need to be an exterior boundary to the geometry. On such boundaries, the normal direction as defined by the normal vector variables does not necessarily have to be outward pointing.

Boundary Flux/Source

Enter the flux term g.

Boundary Absorption/Impedance Term

Enter the absorption or impedance term q.