Hi,
I'd study the acoustic behavior of ducts and mufflers, in order to have more accurate solutions than a 1D approach. How can I simulate an anechoic outlet?
I tried with zeroGradient boundary (I used sonicTurbFoam), but I think that it is non physical and there's a little reflection.
Thank you.

Marco

You may find pressureTransmissive more appropriate. It uses a simplified NSCBC formulation to allow outgoing pressure waves to pass through the outlet boundary but only handles pressure waves not enthalpy, entropy etc. waves which would make the implemention much more tricky.