Distributed computing using multiple GPUs is now supported when solving models using the Accelerated solver formulation available with the Pressure Acoustics, Time Explicit interface. This is the case both for multiple GPUs on one machine or for GPUs set up in a cluster architecture. The accelerated formulation, when solving on a CPU, is now also available for cluster architectures. This gives important performance gains when solving large transient acoustic models, for example, in room acoustic or car cabin acoustic problems.

On Windows, it is now possible to import and use CFD analysis data in the CGNS (CFD General Notation System) format in a COMSOL Multiphysics model. Importing this data is done by combining the new Imported Fluid Flow interface with the new CFD Data (CGNS) function. The Imported Fluid Flow interface handles the correct and consistent mapping of the data onto the computational mesh. If used in combination with the built-in multiphysics couplings (Background Fluid Flow Coupling or Aeroacoustic Flow Source Coupling), the imported flow data will also be used in subsequent aeroacoustics models just as if the flow was computed by one of the Fluid Flow interfaces. Data can also simply be imported onto the computational mesh and used, for example, as a pressure load in a subsequent vibroacoustic analysis.

Periodic Port is a new dedicated feature used to model transmission, reflection, and scattering problems for periodic structures such as absorbers and diffusers. The feature is, in particular, interesting for diffusers, as it can split the reflected energy into specular and nonspecular directions. The periodic port handles plane wave incidence on the structures as well as all reflected and transmitted diffraction orders. The diffraction orders are captured using the Diffraction Order Port subfeature to the Periodic Port condition. The Periodic Port condition is set up together with a Periodic Condition with the Floquet periodicity (Bloch periodicity) option.

The Poroacoustics feature is now also available in the Pressure Acoustics, Transient interface. It was previously only available for the Pressure Acoustics, Time Explicit interface. The feature has the same functionality and options in both interfaces.

In the Poroacoustics feature, in both the Pressure Acoustics, Transient and the Pressure Acoustics, Time Explicit interfaces, two new options are available when setting up a porous material. The Johnson–Champoux–Allard (JCA) and the Johnson–Champoux–Allard–Lafarge (JCAL) models extend the previous User defined option. When the new models are selected, the underlying partial fraction approximation is now automatically computed based on the usual poroacoustic material parameters for the two models.

In all the linearized Euler physics, two formulations can now be selected. Select the Linearized Euler formulation as either the Full linearized Euler (the default) or the Linearized perturbed compressible equations (LPCE) (the new formulation). The first formulation is valid for all Mach numbers (as long as there is not shock formation), while the second is only valid for low Mach numbers (Ma < 0.3). The second formulation has some additional stability properties, as vorticity waves cannot propagate (they are not supported by the equations in this limit).

The stabilization in the Linearized Euler, Frequency Domain and the Linearized Euler, Transient interfaces has been improved to a more consistent formulation. In the time domain, a new Limit small time steps effect on stabilization time scale option can be selected to remedy issues in models with a very small time scale.

The so-called Brambley impedance model is now available in Linearized Potential Frequency Domain; it offers an extension of the classical Ingard–Myers impedance condition. Where the Ingard–Myers condition assumes an infinitely thin boundary layer of the background flow, the new Brambley (finite boundary layer) impedance model option approximates the boundary layer with a finite linear profile.

The Aeroacoustic Flow Source now supports the RANS-EVM SST turbulence model with the Scale-adaptive simulation option. The model can be selected along with LES and DES as input.

It is also possible to add a Window Function to the Aeroacoustic Flow Source. When the aeroacoustic flow source region is compact — that is, it is not selected in the entire acoustic domain — it can be necessary to use a window function to truncate the aeroacoustic source terms in a consistent manner. This can often be the case, as it is computationally expensive to resolve the flow source in its full spatial extent.

The new Acoustic–Acoustic Boundary multiphysics coupling can be used to couple any acoustic interfaces where the coupling condition is continuity in pressure: That is, Pressure Acoustics, Frequency Domain; Pressure Acoustics, Transient; Pressure Acoustics, Boundary Elements; and Thermoviscous Acoustics, SLNS Approximation. Model configurations coupling two interfaces of the same kind are also possible with this feature.

The default Wall feature in the Ray Acoustics interface has been updated to a more user‑friendly version when working with acoustic ray-tracing problems. Input for scattering and absorption coefficients are now the default. The old wall feature, with all its advanced modeling options, still exists and has been renamed to General Wall.

The Material Discontinuity feature is no longer the default in the Ray Acoustics interface. A new option for modeling a thin absorbing structure has been added. It is possible to directly enter the transmission coefficient T and the reflection coefficient R. This is useful for modeling, for example, screens or curtains. If a model contains several materials, then manually add the Material Discontinuity feature on the interior boundary for a correct physical description.

The Stabilized formulation is now the default when modeling with the Pressure Acoustics, Boundary Element interface. The stabilized formulation has been improved, including the default solver configuration. This gives important performance improvements. Note that interior conditions are not available for the stabilized formulation; if needed, disable the formulation.

When solving mode analysis problems to, for example, compute a dispersion diagram, a new Mode following option is available in the Filtering and Sorting section of the study step. This option is useful for a large range of acoustic problems.

All the port conditions in acoustics (available in Solid Mechanics; Pressure Acoustics, Frequency Domain; Thermoviscous Acoustics, Frequency Domain; and Linearized Potential Flow, Frequency Domain) now automatically include and support evanescent as well as propagating modes. This in general gives a better representation of the acoustic field at the port near cuton/cutoff frequencies and when the port is located close to sources or boundaries.