New Functionality in Version 4.3a

  • New fluid model, Boundary layer approximation, for pressure acoustics that you can use for modeling the thermal and viscous losses at boundaries of a duct as a bulk loss (an equivalent fluid). You can choose between wide duct and narrow duct approximations
  • Enter viscous characteristic length directly in Biot equivalent fluid models: It is now possible to enter the viscous characteristic length Lv or the viscous characteristic length parameter s.
  • Domain heat sources are now available in the physics interfaces for thermoacoustics. Heat sources in the domain are useful when modeling optoacoustics and acoustic heat exchangers. In connection with this addition of domain heat sources, the symbols for acoustic monopole dipole volume sources in pressure acoustics have changed (see below).
  • Editing of advanced pressure acoustics equation settings when the equation form is set to Frequency domain in the Pressure Acoustics node’s settings window. You can then edit the expression for the scaling and the order of the non-reflecting boundary condition approximation, which is necessary for a correct set up of the modal solver.

New and Updated Models

  • A model (bk_4134_microphone) of the Brüel & Kjær 4134 condenser microphone, comparing the modeled sensitivity level to measurements performed on an actual microphone, which are in good agreement. The membrane deformation, pressure, velocity, and electric field are also determined.
  • A model (probe_tube_microphone) of a probe tube attached to a microphone. This model requires the Acoustics Module and the Pipe Flow Module.
  • An example (nonlinear_acoustics_westervelt_1d) demonstrating how to model transient nonlinear propagation of finite-amplitude acoustic waves in fluids, solving a 1D Westervelt equation.
  • A model (piezoacoustic_spherical) of a spherical piezoacoustic transducer. The device is poled along the radial direction of the sphere, requiring the definition of a new local system of coordinates.
  • A model (acoustics_particulate_filter) demonstrating acoustics of a particulate-filter-like system. This updated version computes the acoustic transmission loss through a particulate-filter-like system using the Poroelastic Waves user interface.

Backward Compatibility vs. Version 4.3

  • TThe symbols for the acoustics monopole (Qm; was Q) and dipole (qd; was q) volume sources in pressure acoustics have changed.
  • The default value for the Typical wave speed property in the Acoustic-Piezoelectric Interaction, Frequency Domain interface has changed to 343 m/s.