The Acoustic–Solid Interaction, Time Explicit Interface
The Acoustic–Solid Interaction, Time Explicit multiphysics interface () combines Pressure Acoustics, Time Explicit and Elastic Waves, Time Explicit together with the Acoustic–Structure Boundary, Time Explicit multiphysics coupling. The physics interface is available for 3D and 2D geometries.
Acoustic–structure interaction or ASI refers to a multiphysics phenomenon where the acoustic pressure causes a fluid load on the solid domain, and the structural acceleration acts on the fluid domain as a normal acceleration across the fluid-solid boundary. The Acoustic–Solid Interaction, Time Explicit interface can, for example, be used to determine the transmission of sound through an elastic structure or solve for the coupled vibroacoustics phenomena present in an ultrasonic transducer or flowmeter.
The discontinuous Galerkin time explicit method enables efficient computation of acoustically large models (containing many wavelengths) in the time domain. The formulation of the governing equations, effectively requires the acoustics pressure and velocity variations in the fluid domain to be coupled with the structural velocity and strain variations in the solid domain.
A dedicated multiphysics coupling condition is readily defined for the fluid-solid boundary and sets up the continuity in velocity and normal stress.
When a predefined Acoustic–Solid Interaction, Time Explicit interface is added from the Acoustics>Acoustic–Structure Interaction branch of the Model Wizard or the Add Physics windows, the Pressure Acoustics, Time Explicit and Elastic Waves, Time Explicit interfaces are added to the Model Builder. In addition, the Multiphysics Couplings node is added, which automatically includes the Acoustic–Structure Boundary, Time Explicit multiphysics coupling.
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–Structure Boundary, Time Explicit, the Selection on the multiphysics coupling is automatically set to All boundaries. In this way, the multiphysics coupling is automatically active on all boundaries with Pressure Acoustics, Time Explicit on one side and Elastic Waves, Time Explicit 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 Multiphysics adds an empty Multiphysics Couplings node. You can choose the available multiphysics couplings, but you need manually to 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 Couplings 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 Couplings
The Acoustic–Structure Boundary, Time Explicit multiphysics coupling is described in the Multiphysics Couplings chapter. Note that a pair version of the multiphysics coupling exists that can be used for assemblies: Pair Acoustic–Structure Boundary, Time Explicit.
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 Pressure Acoustics, Time Explicit Interface are listed in the section Domain, Boundary, Edge, and Point Nodes for the Pressure Acoustics, Time Explicit Interface.
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The available physics features for The Elastic Waves, Time Explicit Interface are listed in the section Domain, Boundary, Edge, Point, and Pair Nodes for the Elastic Waves, Time Explicit Interface.
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Theory Background for the Pressure Acoustics Branch
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Theory for the Elastic Waves, Time Explicit Interface