Thermoacoustic-Shell Interaction is a new predefined multiphyscis
interface in 3D for models that contain thermoacoustic domains and pressure acoustic domains as well as
shells. The Thermoacoustic-Shell Interaction interface supports three types of shells: exterior shells,
interior shells, and uncoupled shells (shells on boundaries that are not connected to any acoustic domain).
Boundary mode analysis study for Thermoacoustics, Frequency Domain
2D and 1D axisymmetric models, which you can use to determine propagating and nonpropagating out-of-plane modes.
New and redesigned periodic boundary conditions for solid, piezo,
piezo-acoustic, and thermoacoutics applications, including the following new types of periodic boundary conditions:
General Floquet periodicity conditions.
Cyclic symmetry condition for sector periodicity and dynamic cyclic symmetry.
Also, an option to prescribe the periodic conditions on the entire
displacement vector has been added (it is the new default option).
New far-field plots that are generated independently of the models’
mesh elements have been added. These plots make it easier to define far-field plots, and you can also
create 3D polar plots directly in the COMSOL Desktop. The Bessel Panel and Cylindrical Subwoofer models have been updated to include new far-field plots.
Default far-field plots are generated when a far-field domain feature is available in the model.
New and updated intensity variables for the Pressure Acoustics and Aeroacoustics interfaces:
Intensity (RMS)
Intensity magnitude (RMS)
Instantaneous intensity
Instantaneous intensity magnitude
Low-reflecting boundary condition, mainly intended for letting waves pass
out from the model without reflection in time-dependent analysis for acoustics and structural mechanics. As a
default, it takes material data from the domain in an attempt to create a perfect impedance match for both pressure waves and shear waves
New Models
Generic 712 Coupler: The model is based on an actual Brüel and Kjær device and the results are compared to measurements.
Condenser Microphone: Model using the new Membrane interface (requires the Structural Mechanics Module and the AC/DC Module).
Porous Absorber: Model that demonstrates the use of the new Floquet periodic boundary condition.
Acoustic Scattering: Model using the new far-field plots.
Backward Compatibility vs. Version 4.2a
The far-field variables pfar and Lp_far get new names with full scope. They are now referred to as acpr.ffc1.pfar and acpr.ffc1.Lp_far, respectively. Any user Model Java-files that use the old variable names in expressions (such as expressions to plot or evaluate expressions including these variables) will require a manual update.
The default Coordinate stretching type for a Perfectly Matched Layer has changed to Polynomial.
Backward Compatibility vs. Version 4.2
The Pressure Acoustics and Transient Pressure Acoustics interfaces in version 4.2 are now called Pressure Acoustics, Frequency Domain and Pressure Acoustics, Transient, respectively. The names for other acoustics interfaces have changed in a similar way.
When creating an orthotropic or anisotropic linear elastic material in the Elastic Waves or Poroelastic waves interfaces, the default is now to use Voigt notation. This will cause a model created using an old Java script to fail. Adjust the Java file so that it explicitly selects Standard notation instead of Voigt notation when using orthotropic or anisotropic materials.
