Enter the boundary mode.
Specify boundary conditions for the selected boundaries. If no boundaries are selected, the entered boundary condition applies to all boundaries.
Show Edge Labels
Toggle the labeling of the edges (outer boundaries and subdomain borders) on/off. The edges are labeled using the column number in the Decomposed Geometry matrix.
Show Subdomain Labels
Toggle the labeling of the subdomains on/off. The subdomains are labeled using the subdomain numbering in the Decomposed Geometry matrix.
Remove Subdomain Border
Remove selected subdomain borders.
Remove All Subdomain Borders
Remove all subdomain borders.
Export Decomposed Geometry, Boundary Cond's
Export the Decomposed Geometry matrix
Specify Boundary Conditions opens a dialog box where you can specify the boundary condition for the selected boundary segments. There are three different condition types:
Generalized Neumann conditions, where the boundary
condition is determined by the coefficients
to the following equation:
In the system cases,
q is a 2-by-2 matrix
g is a 2-by-1 vector.
Dirichlet conditions: u is specified on the boundary. The boundary condition equation is hu = r, where h is a weight factor that can be applied (normally 1).
In the system cases,
h is a 2-by-2 matrix
r is a 2-by-1 vector.
Mixed boundary conditions (system cases only), which
is a mix of Dirichlet and Neumann conditions.
a 2-by-2 matrix,
g is a 2-by-1 vector,
a 1-by-2 vector, and
r is a scalar.
The following figure shows the dialog box for the generic system PDE (Options > Application > Generic System).
For boundary condition entries you can use the following variables in a valid MATLAB® expression:
The 2-D coordinates
A boundary segment parameter
proportional to arc length.
s is 0 at the start
of the boundary segment and increases to 1 along the boundary segment
in the direction indicated by the arrow.
The outward normal vector components
If you need the tangential vector, it can be expressed using
ny since tx = –ny and ty = nx.
If the boundary condition is a function of the solution
In the nongeneric application modes, the Description column contains descriptions of the physical interpretation of the boundary condition parameters.