Guys,
I was seeing this video to know how COMSOL can calculate the Transmission Loss of a muffler
https://www.youtube.com/watch?v=jrk_9SIn0aw
but what about the frequency range between 1-10000? for example if the cut-off frequency of the muffler is 3000, then such tutorial can not help, can it?
René Christensen Thank you for response. Here is a link to a method named "transmission matrix":
https://en.wikipedia.org/wiki/Transmission_loss_(duct_acoustics)#A_simple_example
As it's said in that link:
"Also note that the above calculation is only valid for low-frequency range because at low-frequency range the sound wave can be treated as a plane wave. The TL calculation will start losing its accuracy when the frequency goes above the cutoff frequency, which can be calculated as f c = 1.84 c π D {\displaystyle f_{c}=1.84{c \over {\pi D}}} 📷"
In that video, the author uses a "plane wave radiation" boundary. I afraid if the method of comsol could be valid for all frequency ranges. What do you think?
I think this blog post can help https://www.comsol.com/blogs/using-the-port-boundary-condition-in-acoustic-waveguide-models/
and in particular this model from COMSOL application library https://doc.comsol.com/5.6/docserver/#!/com.comsol.help.models.aco.duct_right_angled_bend/duct_right_angled_bend.html
In short, you need take into account more modes propagating in your waveguide.
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