PAFEC VibroAcoustics - Import of CAD data to create horn model


Third party pre-processing software can be used to import CAD data and generate a mesh, which can be straightforwardly converted to PAFEC data file format.

The example below demonstrates the creation of a horn model. Symmetry has been utilised, therefore only a quarter model is required.


1. Import CAD geometry


2. Define surfaces from imported lines and curves



3. Define volume from surfaces


4. Assign appropriate mesh size
and generate mesh



Please note, it may be necessary to repair CAD data if edges do not meet at verticies



5. Convert to PAFEC format


The wizard ‘Horn.exe’ converts the mesh to PAFEC data file format and adds additional modules to describe:

  • Rigid piston at throat
  • ‘Pancake’ of acoustic finite elements at mouth.
  • Acoustic boundary element layer at mouth.
  • Symmetry planes
  • Type of excitation
  • Position of microphone nodes
  • Frequency range and step



6. Run PAFEC analysis and post-process results


Various result types and formats are available, including:

  • Pressure contours, which may be animated and/or displayed on cutter planes through the volume of the fluid.
  • Pressure graphs



7. Position of microphone nodes


The position of the microphone: in this instance two quarter circles at 90o to each other, at 5o steps, 1m from the mouth of the horn.



8. Graph of SPL (dB) v Frequency (Hz) for selected microphone nodes