Pressure, Interface
Use the Pressure, Interface node to specify the pressure on the exterior interfaces of a layered shell or on the interfaces between its layers.
In many cases the distribution of pressure is known, giving a Dirichlet condition p = p0 where p0 is a known pressure given as a number, a distribution, or an expression involving time, t, for example.
Interface Selection
Set the interfaces for which the pressure should be specified. These can be internal interfaces between layers or the top and bottom surfaces.
The available options in the Apply to list are Top interface, Bottom interface, Exterior interfaces, Interior interfaces, All interfaces, and Selected interfaces. With the last option you can select any set of interfaces for a given layered material, by clearing the checkboxes corresponding to layer interfaces where the node should not be applied in the Selection table. The top and bottom interfaces refer respectively to the upside and downside of the boundary, defined from the orientation of the normal vector. You can visualize the selected interfaces by clicking the Layer Cross Section Preview () and Layer 3D Preview () buttons.
For a general description of layer and interface selections, see Layer and Interface Selection Tools in the Heat Transfer Module User’s Guide.
Pressure
Enter a value or expression for the Pressure p0 (SI unit: Pa).
Constraint Settings
To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog.
For detailed information about the Constraint settings menu see section Constraint Settings in the COMSOL Multiphysics Reference Manual.