The Interior Dirichlet Boundary Condition, which is only available for interior boundaries in the Stabilized Convection-Diffusion Equation interface, specifies values of u on the upside and downside of interior boundaries in the domain: uu = ru and ud = rd.

The red arrows in the Graphics window point toward the downside from the upside.

Enter values or expressions for the prescribed values on the downside and upside in the associated text fields for rd and ru under Downside and Upside, respectively.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog box. This section contains settings for specifying the type of constraint. See Constraint Settings for more information.