The General Interior Flux node, found under the More submenu, adds the most general interior boundary condition for the Pressure Acoustics, Time Explicit model, as it is formulated (in the conservative form) for the discontinuous Galerkin method (dG). The condition defines the normal flux gp and gu at an interior boundary. It should include any necessary numerical flux (as it overrides the Lax–Friedrichs flux). Care should be taken when using this advanced condition as the method is sensitive to proper formulation of boundary conditions.

Enter the expression for the components of the Flux vector gp and gu.