Adding and Inserting Physics Interfaces
The Add Physics Window
The Add Physics window is similar to the Select Physics window accessed through The Model Wizard. It has the same physics interfaces available. This window is a quick way to add physics interfaces to models.
To open the Add Physics window:
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Right-click a Component node and choose Add Physics.
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From the Home toolbar, click Add Physics
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Select Windows>Add Physics.
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From the Physics toolbar, click Add Physics .
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Right-click a Component node and choose Add Physics.
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In the Model toolbar, click Add Physics .
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In the Physics Contextual Toolbar, click Add Physics .
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Select Windows>Add Physics.
The Add Physics toolbar button is a toggle button: Click it again to close the Add Physics window.
You can also click Add Mathematics () on the Physics or Model toolbar, or right-click a Component node and choose Add Mathematics to open the Add Physics window with the Mathematics branch selected and expanded.
To Add Physics Interfaces to a Model Component
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In the Add Physics window, either enter a Search term or navigate the tree to locate the physics interface to be added to the Component.
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 the Search button to list all the interfaces with the search term.
The contents of the Add Physics window depends on the space dimension of the active model component. If there are no Component nodes in the model, the list of physics interfaces is empty.
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Once you have clicked a physics interface, review and optionally modify any dependent variable names in the Dependent Variables section and, for some physics interfaces, specify the number of dependent variables. For PDE interfaces under Mathematics, you can also click the Units tab to specify units for the equation by defining a unit through a physical quantity for the dependent variable and the source term. See Units for more information about these settings. Here, and in the Dependent Variables section in the Settings window for the physics interfaces (where you can also change their names), the units for the dependent variables are displayed within parentheses.
If you select multiple physics interfaces, the Dependent Variables section is not available.
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When there is already a physics interface added to the Component, the existing Studies are listed under Physics interfaces in study. By default, the studies appear with a check mark () in the Solve column, which indicates that the study solves for the dependent variables in the physics interface. Click in the column to clear the check mark and exclude the physics interface from that study.
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Click the Add to Component or Add to Selection buttons.
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If you click Add to Component, the physics interfaces are added to the Model Builder and become active in the entire model component’s geometry by default. You can also press Enter to add the physics components to the component.
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If you click Add to Selection, the physics interfaces are added to the Model Builder with a selection taken from the selected geometric entities in the Graphics window. This is a method called preselection.
Copying, Pasting, and Inserting Physics Interfaces
You can copy and paste physics interfaces within a COMSOL Multiphysics session and also between COMSOL Multiphysics sessions, as long as the copied physics interface information remains in the clipboard.
To copy a physics interface with all its subnodes, right-click the physics interface node and choose Copy (or, for Windows users, click Copy on the Quick Access Toolbar). You can then paste it in the same or a new COMSOL Desktop session by right-clicking a compatible Component node and choosing, for example, Paste Solid Mechanics (or, for Windows users, click, for example, Paste Solid Mechanics on the Quick Access Toolbar).
It is also possible to insert physics interfaces from another COMSOL Multiphysics model into a model component. To do so, right-click a Component node and choose Insert Physics () or Insert Physics From ().
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In the first case, an Insert Physics dialog box appears where you can browse or type the path and name of the COMSOL Multiphysics model file from which you want to insert physics interfaces in the Model field. Select one or more of the physics interfaces in the model from the Physics list in the Insert Physics dialog box and then click OK to insert them into the current model. The list includes the space dimension for the physics interface so that you can select compatible physics interfaces.
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In the last case, a fullscreen Select Model window opens, where you can insert a physics interfaces from an existing database, add a new database, or browse for models to insert physics interfaces from. Select one or more of the physics interfaces in the model from the Physics list in the Insert Physics dialog box and then click OK to insert them into the current model. See also The Select Model Window.
You can insert a physics interface from another space dimension if it is applicable in the component you insert it into. Most physics applicable in 2D axial symmetry is applicable in 3D, so an interface specified in a 2D axisymmetric component can therefore be inserted in a 3D component.
Some aspects when inserting or pasting a physics interface into an existing model component:
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All selections of a physics interface and its physics features depend on the geometry they belong to. When you insert or paste a physics interface into another component and geometry, there is a high risk that selections change or become empty.
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Any references to named selections will be broken, and no selection nodes are included automatically in the insertion process.
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All use of global parameters, functions, variables, materials, multiphysics couplings, and coordinate systems will be invalid after the insertion process unless an item with the same name exists in the target component. No attempt is made to automatically include any item in the insertion process. Materials should be of minor importance if the physics interfaces consistently use the option From material in all their material property settings.
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Some physics features are not applicable in all dimensions, so these will simply be ignored. You will be notified about this in the message dialog box.
Altogether, these aspects may cause an insert or paste operation to be incomplete to some degree. In some cases, the difference is reported in a message dialog box after the insertion process has finished. Click Cancel in this dialog box to revert the insertion process.
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Creating a New Model
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Physics Interface Guide