Acoustic FEM-BEM Boundary
The Acoustic FEM-BEM Boundary coupling () is used to couple the FEM based Pressure Acoustics, Frequency Domain interface to the BEM based Pressure Acoustics, Boundary Elements interface. The coupling works as a bidirectional coupling as most other multiphysics couplings in the Acoustics Module. The coupling prescribes continuity in the total pressure
where pt.bem is the total pressure in the BEM based pressure acoustics interface and pt,fem is the total pressure in the FEM based pressure acoustics interface.
Using this coupling the strengths of the FEM and BEM methods can be used where they apply best. For example, the FEM based interface should be used in interior domains or to model porous domains with the Poroacoustics feature. When coupled to an open space where radiation occurs it can be advantageous to use BEM here. This is, for example, the case when modeling loudspeaker cabinets and enclosures that have a vent.
Another powerful application of the FEM-BEM coupling is to use the BEM based interface, when coupled to Pressure Acoustics, Frequency Domain, as a combined radiation condition and far-field calculating feature. The radiation condition will be perfect as the BEM problem is solved exactly and the BEM variables can be used in postprocessing instead of the usual far-field variables. The BEM variables like, for example, the sound pressure level pabe.Lp can be used in the existing far-field plots.
Settings
See Settings for further details about Label and Name.
The default Name (for the first multiphysics coupling feature in the model) is apb1.
Coupled Interfaces
This section defines the physics involved in the multiphysics coupling. The Boundary elements acoustics and Finite elements acoustics lists include all applicable physics interfaces. See the Coupled Interfaces in Acoustic-Structure Boundary for details.