Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Evaluatig Noise Reduction and Insertion Loss
Posted 23 juil. 2012, 02:13 UTC−4 Acoustics & Vibrations Version 4.1 0 Replies
Please login with a confirmed email address before reporting spam
I'm trying to evaluate Noise Reduction and Insertion Loss for open-end tube onto acoustics fields.
fortunately, I did calcalate Transmission Loss successfully. Because setting the outlet tube boundary contion is pretty simple. I assume anechoic termination at the end of tube, so I put the impedance Z_0 likes rho*c(speed of sound in air).
But I cant use that impedance when I calculate Noise Reduction and Insertion Loss, because these cases are NOT anechoic terminatio. So I put the equation likes..
Z_0 = rho*c*(0.25*(k*r0)^2+j*0.6*k*r0) (subject to k*r0<0.5)
This equation came from Levine and Schwingers' study(1947).
I tryed to calculatre this problem so many times whit COMSOL, but I cannot reach satisfy results.
That contains too many negative values.I expect your briliant advices.
Best Regards
Hello Kee Seung Oh
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.