The Interior Flux boundary condition can be used on interior boundaries only. With this node, the boundary condition is enforced according to:
where g can be specified. Here,
n is outward normal seen from the downside, so it should be read as
−n ·
Γ = g for a downside of an interior boundary and as
−n ·
Γ = −g on the upside of an interior boundary. If a dependent variable is used in this expression (without
up or
down operators), an implicit mean operation is invoked taking the average of the up and down values.
where r and
l denote the right and left side of the interface, respectively.
Here dnx means the downside normal (
dnx=-unx).