Domain and Boundary Nodes for the Mixture Model Interfaces
The following domain and boundary nodes are available from the Physics ribbon toolbar (Windows users), Physics context menu (Mac or Linux users), or right-click to access the context menu (all users).
In general, to add a node, go to the Physics toolbar, no matter what operating system you are using. Subnodes are available by clicking the parent node and selecting it from the Attributes menu.
Domain
•
Mixture Properties
•
Mass Transfer
•
Volume Force (described for The Laminar Flow Interface)
•
Gravity
•
Initial Values
Boundary
The boundary types for the mixture flow variables, described in this section, are:
•
Wall (the default boundary condition feature)
•
Inlet
•
Outlet
•
Symmetry
•
Periodic Flow Condition
•
Interior Wall
Pair
•
Mixture Continuity
For the flow variables, the velocity and the pressure, the boundary conditions correspond to those defined for single phase flow (see Domain, Boundary, Pair, and Point Nodes for Single-Phase Flow). There is also a point constraint for the pressure, which is useful if no other boundary condition in the model includes a pressure level constraint.
The following boundary conditions for the dispersed phase are available for all boundary condition types except symmetry and interior wall. These are described in more detail in the Theory for the Mixture Model Interfaces.
•
 Dispersed phase concentration (the default condition for inlets)
•
 Dispersed phase flux
•
 Dispersed phase outlet (the default condition for outlets)
•
 No dispersed phase flux (the default condition for walls)
•
 Symmetry
For 2D axisymmetric components, COMSOL Multiphysics takes the axial symmetry boundaries (at r = 0) into account and automatically adds an Axial Symmetry node to the component that is valid on the axial symmetry boundaries only.