The Model Wizard
The Model Wizard helps you build a model by choosing the space dimension, physics interfaces, and the study you want to use. In the Model Wizard you Select Space Dimension, Select Physics, Review Physics Interface, and finally Select Study.
Select Space Dimension
1
Open the Model Wizard (see Open a New Window to Begin Modeling).
2
On the Select Space Dimension page, click to choose the Component geometry dimension: 3D, 2D axisymmetric, 2D, 1D axisymmetric, 1D, or 0D.
Component Nodes by Space Dimension
The Component node has different icons based on space dimension 0D () (no space dimension), 1D (), 1D axisymmetric (), 2D (), 2D axisymmetric (), and 3D ().
0D is used for interfaces modeling spatially homogeneous systems such as chemical reacting systems, electrical circuits, and general ODEs and DAEs. If you want to import a geometry, this is done in the Model Builder, but make sure you choose spatial dimensions that this geometry exists in. Remember, not all physics interfaces are available for all space dimensions.
Also add a Component node to the Model Builder:
•
By right-clicking the Root node () and selecting it from the Add Component menu.
•
On the Home toolbar select an option from Add Component list.
Select Physics
On the Select Physics window, there are different ways to select one or several physics interfaces to add to the model. There are also interfaces for PDEs, ODEs, and DAEs under the Mathematics branch.
The tree organizes the available physics interfaces by application areas such as fluid flow, heat transfer, and structural mechanics. The physics interfaces found in the modules your license supports display in the different application areas. In some cases, licensing of a module adds physics interfaces to these application areas as well as attributes to existing physics interfaces, which are enhanced with additional functionality. The Recently Used  branch lists the last five physics interfaces used in recent modeling sessions. You can also enter a text string in the search field and click Search to list all the physics interfaces with the term.
Once a physics interface is selected, there are several options to continue; see Figure 2-12. Click to select one of these buttons:
Icon and Name
Action
Add
Click to add the physics interface to the Added physics interfaces list, or right-click and select Add physics. Add as many physics interfaces as you want. You can use the Review Physics Interface page to edit the Dependent Variables as required. Click Remove as required to organize the physics interfaces in the list.
Space Dimension
Click to go back to the Select Space Dimension page.
Study
Click to choose the study for the model.
Done
Click to add the physics interface without a study.
Cancel
Click to return to the COMSOL Desktop.
Help
Click to open the context-based Help window.
Also add physics interfaces from the Model Builder and The Add Physics Window:
•
On the Home toolbar, click the Add Physics button.
•
By right-clicking the Component node and selecting Add Physics.
Figure 2-12: The Select Physics and Review Physics Interface windows in the Model Wizard.
Review Physics Interface
Under Added physics interfaces (see Figure 2-12), click any interface to open the Review Physics Interface page. Here you can review and optionally modify any Dependent Variables names and, for some physics interfaces, specify the number of dependent variables. For other physics interfaces you can edit both the name of the field and the field components. Examples of fields with components are the displacement field in a Solid Mechanics interface and the Velocity field for a Laminar Flow interface.
To remove a physics interface already selected, highlight it in the list and click Remove under the table.
Select Study
On the Select Study page, click to select the type of study to perform. The available options depend on the set of physics interfaces included in the model. Some study types are applicable to all physics interfaces for which you choose to solve, while others are not, but all are in some way available. You can select the study type from one of the following branches (see Figure 2-13):
•
Preset Studies — Studies suggested by a single physics interface if only one has been chosen.
•
 Preset Studies for Selected Physics Interfaces  — Studies applicable to all physics interfaces that you have chosen to solve for.
•
Preset Studies for Selected Multiphysics — Studies applicable to the multiphysics couplings that you have chosen to solve for.
•
Custom Studies — In some study types, not all physics interfaces solved for can generate suitable equations. The custom studies branch accounts for those study types:
-
 Preset Studies for Some Physics Interfaces — The study types recognized by some, but not all, of the physics interfaces being solved for.
-
Empty Study
-
 Other studies — Any fundamental study types (Stationary, Time Dependent, Eigenfrequency, Eigenvalue and Frequency Domain) which are not applicable to any of the physics interfaces being solved for. There is also an empty study type.
Figure 2-13: The Select Study page in the Model Wizard.
Once a study is highlighted, information about it displays to the right of the window and it is included under Added study. There are several options to continue.
Icon and Name
Action
Physics
Click to go back to the Select Physics and Review Physics Interface window.
Done
Click to exit the Model Wizard.
Cancel
Click to return to the COMSOL Desktop.
Help
Click to open the context-based Help window.
Also add physics interfaces from the Model Builder and The Add Physics Window:
•
On the Home toolbar click the Add Physics button.
•
By right-clicking the Component node and selecting Add Physics.
After clicking Done, the Model Builder window displays a model tree with a set of default nodes in the Component branches: Definitions, Geometry, Materials, Mesh, and nodes based on the physics interfaces selected (see Figure 2-14). The Component nodes and branches form the sequence of operations that define the model.
Figure 2-14: After clicking Finish, a 3D Component with Electric Currents and Heat Transfer in Solids interfaces, Multiphysics couplings, and a Stationary study added to the Model Builder.
Also add a study from the Model Builder and The Add Study Window:
•
By right-clicking the Root node and selecting Add Study.
•
On the Home toolbar click the Add Study button.
•
Building a COMSOL Multiphysics Model
•
The Component Node
•
The Add Physics Window
•
The Add Study Window
•
The Model Builder