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.
•
In 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, and other mathematical interfaces for equation-based modeling under the Mathematics branch.
Once one or more physics interfaces are selected, there are several options to continue; see Figure 2-13. Click to select one of these buttons:
Icon and Name
Action
Add
Double-click to add the selected physics interface to the Added physics interfaces list, or right-click and select Add physics to add one or more selected physics interfaces. You can also add the selected physics by pressing Enter. 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 New page of the Model Wizard.
Help
Click to open the context-based Help window.
You can also add physics interfaces from the Model Builder and The Add Physics Window:
•
In the Home toolbar, click the Add Physics button.
•
By right-clicking the Component node and selecting Add Physics.
Figure 2-13: The Select Physics and Review Physics Interface windows in the Model Wizard.
Review Physics Interface
Under Added physics interfaces (see Figure 2-13), 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. You can also double-click the study to select it and close the Model Wizard. 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. The most applicable and common studies, such as Stationary, appear at the top of the list under General Studies. You can also select a study type from one of the following branches (see Figure 2-14):
•
General Studies — General studies that are the most applicable for the selected physics interfaces.
•
 Preset Studies for Selected Physics Interfaces  — Studies applicable to each physics interface that you have chosen to include. These preset studies appear under subnodes for each physics interface or under Suggested by Some Physics Interfaces.
•
Preset Studies for Selected Multiphysics — Studies applicable to the multiphysics couplings that you have chosen to solve for.
•
More Studies — Any fundamental study types (Stationary, Time Dependent, Eigenfrequency, Eigenvalue and Frequency Domain) that are not applicable to any of the physics interfaces being solved for. Also, this branch can contain some advanced composite 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 — An empty study that will not perform any type of study unless you add some study steps to it.
Figure 2-14: 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 New page of the Model Wizard.
Help
Click to open the context-based Help window.
Also add physics interfaces from the Model Builder and The Add Physics Window:
•
In 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 2-15). The Component nodes and branches form the sequence of operations that define the model.
Figure 2-15: After clicking Done, a 3D Component with Electric Currents, Heat Transfer in Solids interfaces, and a Stationary study is 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.
•
In 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