Who should attend:

New Actran users. Experience with Actran is not required. Acoustics background is preferable.

Overview:

Contrary to classic 1D modeling method, the 3D modeling of exhaust lines with Actran takes into account flow gradients, complex geometries and can reach high frequencies. You will learn all along this session how to predict pipe noise as well as shell noise of a complete exhaust line. You will be able to compute the acoustic transmission loss as well as the exterior radiation of the exhaust. Modeling perforated sheets and insulating materials will be also addressed.

Topics covered:

  • Introduction to the acoustic and the vibro-acoustic simulation, including viscothermal effects
  • Non-reflecting boundary conditions: infinite elements or APML (exterior radiation), modal basis (semi-infinite ducts)
  • Acoustic excitations:
    - Based on the reflection factor, mode amplitude, pressure, velocity
    - Based on 1D solvers (GT Power, WAVE, …)
  • Acoustic propagation in a steady flow:
    - Introduction to duct modes and cut-off frequencies
    - Import temperature and flow fields
  • Modeling muffler components: perforated plates and foams
  • Introduction to flow turbulences for shell noise and pipe noise
  • Numerical method for increasing the efficiency of a computation: the Transfer Matrix Method