The Acoustic-Thermoviscous Acoustic Interaction, Frequency Domain Interface
The Acoustic-Thermoviscous Acoustic Interaction, Frequency Domain multiphysics interface (), found under the Thermoviscous Acoustics branch () when adding a physics interface, combines the Thermoviscous Acoustics, Frequency Domain and Pressure Acoustics, Frequency Domain interfaces together with the Acoustic-Thermoviscous Acoustic Boundary multiphysics coupling. To couple the two physics and use Thermoviscous Acoustics only where necessary can reduce the computational cost of a model.
The physics interface solves the equations in the frequency domain assuming all fields and sources to be harmonic. Linear acoustics is assumed.
When a predefined Acoustic-Thermoviscous Acoustic Interaction, Frequency Domain interface is added from the Acoustics>Thermoviscous Acoustics branch of the Model Wizard or the Add Physics windows, the Thermoviscous Acoustics, Frequency Domain and Pressure Acoustics, Frequency Domain interfaces are added to the Model Builder.
In addition, the Multiphysics node is added, which automatically includes the multiphysics coupling Acoustic-Thermoviscous Acoustic Boundary.
For details about all the multiphysics couplings in the Acoustics Module, see Multiphysics Couplings.
The use of multiphysics couplings helps improve the flexibility and design options for your modeling. For for details, see The Multiphysics Branch and Multiphysics Modeling Workflow in the COMSOL Multiphysics Reference Manual.
Settings for Physics Interfaces and Multiphysics Couplings
When a predefined multiphysics interface is used, for example Acoustic-Thermoviscous Acoustic Interaction, Frequency Domain, the Selection on the multiphysics couplings is automatically set to All boundaries. In this way, the multiphysics coupling is automatically active on all boundaries with Thermoviscous Acoustics, Frequency Domain on one side and Pressure Acoustics, Frequency Domain on the other.
However, if physics interfaces are added one at a time, followed by the multiphysics couplings, these modified settings are not automatically included.
For example, if the single interfaces are added, COMSOL adds an empty Multiphysics node. You can choose the available multiphysics couplings, but you need to manually select on which boundaries they need to be applied, or select All boundaries to recover the predefined behavior.
Multiphysics couplings are available from the context menu (right-click the Multiphysics node) or from the Physics toolbar, Multiphysics menu.
Physics Interfaces and Multiphysics Couplings
Use the online help in COMSOL Multiphysics to locate and search all the documentation. All these links also work directly in COMSOL Multiphysics when using the Help system.
Multiphysics Coupling
See Acoustic-Thermoviscous Acoustic Boundary in the Multiphysics Couplings chapter.
Physics Interface Features
Physics 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.
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The available physics features for The Thermoviscous Acoustics, Frequency Domain Interface are listed in the section Domain, Boundary, and Pair Nodes for the Thermoviscous Acoustics, Frequency Domain Interface.
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The available physics features for The Pressure Acoustics, Frequency Domain Interface are listed in the section Domain, Boundary, Edge, Point, and Pair Nodes for the Pressure Acoustics, Frequency Domain Interface
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Theory Background for the Pressure Acoustics Branch
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Theory Background for the Thermoviscous Acoustics Branch