Common Physics Interface and Feature Settings and Nodes

There are several common settings and sections available for the physics interfaces and feature nodes (Table 2-4). Some of these sections also have similar settings or are implemented in the same way no matter the physics interface or feature being used. There are also some physics feature nodes (Table 2-5) that display in COMSOL Multiphysics.

In each module’s documentation, only unique or extra information is included; standard information and procedures are centralized in this manual.

	Table 2-4 has links to common sections and Table 2-5 to common feature nodes. You can also search for information: press F1 to open the Help window or Ctrl+F1 to open the Documentation window.

To display additional sections and options for the physics interfaces (and other parts of the model tree), click the button (

) on the and then select the applicable options in the dialog box that opens.

After selecting some options, new or extended sections display on the window when a node is clicked, or additional nodes are made available from the toolbar or context menu. Selecting either adds an settings section or enables nodes in the context menu or toolbar. In many cases these options are described in the individual documentation.

Section	Cross Reference and Notes
Advanced Settings — Pseudo time stepping	Pseudo Time Stepping and Pseudo Time Stepping for Laminar Flow Models
Advanced Settings — Frames	See Frames.
Advanced	This section can display after selecting Advanced Physics Options. The Advanced section is often unique to a physics interface or feature node.
Anisotropic materials	For some User defined parameters, the option to choose Isotropic, Diagonal, Symmetric, or Full displays. See Modeling Anisotropic Materials for information.
Consistent Stabilization	See Stabilization.
Constraint Settings	Constraint Reaction Terms, Weak Constraints, and Symmetric and Nonsymmetric Constraints
Coordinate System Selection	Coordinate Systems Selection of the coordinate system is standard in most cases. Extra information is included in the documentation as applicable.
Dependent Variables	Predefined and Built-In Variables This section is unique for each physics interface, although some interfaces have the same dependent variables.
Discretization	Settings for the Discretization Sections
Discretization — Frames	See Frames.
Equation	Physics Nodes — Equation Section The equation that displays is unique for each interface and feature node, but how to access it is centrally documented.
Frames (Advanced Settings — Frames and Discretization — Frames)	Handling Frames in Heat Transfer and About Frames
Geometric entity selections	Working with Geometric Entities Selection of geometric entities (Domains, Boundaries, Edges, and Points) is standard in most cases. Extra information is included in the documentation as applicable.
Inconsistent Stabilization	See Stabilization.
Settings	Predefined and Built-In Variables Displaying Node Names, Tags, and Types in the Model Builder There is a unique Name for each physics interface.
Material Type	About Using Materials in COMSOL Multiphysics The Settings Window for Material Selection of material type is standard in most cases. Extra information is included in the documentation as applicable.
Model Inputs	About Model Inputs and Model Inputs and Multiphysics Couplings Selection of Model Inputs is standard in most cases. Extra information is included in the documentation as applicable. To define the absolute pressure for heat transfer, see the settings for the Fluid node. To define the absolute pressure for a fluid flow interface, see the settings for the Fluid Properties node (described for the Laminar Flow interface). If you have a license for a nonisothermal flow interface, see that documentation for further information.
Override and Contribution	Physics Exclusive and Contributing Node Types Physics Node Status
Pair Selection	Identity and Contact Pairs Continuity on Interior Boundaries Selection of pairs is standard in most cases. Extra information is included in the documentation as applicable. Contact pair modeling requires the Structural Mechanics Module or MEMS Module. Details about this pair type can be found in the respective user’s guide. If the pair name in the list is followed by (partial) then the feature is only valid on parts of the pair’s geometric entities.
Stabilization — Consistent and Inconsistent	Numerical Stabilization, Numerical Stability — Stabilization Techniques for Fluid Flow and Heat Transfer Consistent and Inconsistent Stabilization Methods

Feature Node	Cross Reference and Notes
Auxiliary Dependent Variable	Auxiliary Dependent Variable
Axial Symmetry	See Symmetry.
Continuity	Continuity on Interior Boundaries and Identity and Contact Pairs. This is standard in many cases. When it is not, the node is documented for the physics interface.
Discretization	Discretization (Node)
Equation View	Equation View The Equation View node’s contents is unique for each physics and mathematics interface and feature node, but it is centrally documented.
Excluded Edges, Excluded Points, and Excluded Surfaces	Excluded Points, Excluded Edges, Excluded Surfaces
Global Constraint	Global Constraint. Also see the Constraint Settings section.
Global Equations	Global Equations
Harmonic Perturbation	Harmonic Perturbation, Prestressed Analysis, and Small-Signal Analysis
Initial Values	Physics Interface Default Nodes, Specifying Initial Values, and Dependent Variables This is unique for each physics interface.
Periodic Condition	Periodic Condition and Periodic Boundary Conditions Periodic Condition is standard in many cases. When it is not, the node is documented for the physics interface.
Pointwise Constraint	Pointwise Constraint. Also see the Constraint Settings section.
Symmetry	Using Symmetries and Physics Interface Axial Symmetry Node. There is also information for the Solid Mechanics interface about Axial Symmetry. This is standard in many cases. When it is not, the node is documented for the physics interface.
Weak Constraint	Weak Constraint. Also see the Constraint Settings section.
Weak Contribution	Weak Contribution (ODEs and DAEs) and Weak Contribution (PDEs and Physics)
Weak Contribution on Mesh Boundaries	Weak Contribution on Mesh Boundaries