Thanks for the reply Greg, but we dont have a physical prototype of the system. This is an academic project where we would like to just build up a model and verify it analytically. Aim is to be able to predict the sound generation mechanism in a ventilation duct with airflow under a given air...
Here is the problem in more detail. We are trying to predict the SPL or SWL coming out from a ventilation grill which opens in to an open space such as a room. The SPL/SWL determination is to be done just at the exit of the grill so we can model it as a noise source. This grill is at the end of...
Hello Again,
I would like to know if someone has any idea of how to predict the sound pressure level for a case where sound is being emmited from three rectangular slits at the end of a long tunnel like a ventilation duct. The slits are very small compared to the dimensions of the tunnel and are...
Hi Greg,
Thanks for the help. Ya i know using RT to characterise a SAC is not very common but this is an exercise we are dealing for academic interest. Ya i have done exactly as u said taken the overall levels against time and tried to fit a straight line to that. This room is not completely...
Hello,
I am trying to analyse the reverberation time of a partially constructed hemi anechoic room. I have taken SPL measurements at various positions in the room using a speaker and one microphone and moving them around in the room at various positions(3 positions for the speaker and 4 for the...
Dear Ajamnia,
Thank you for the help.. i have to do this in two steps.. in one approach i just model it as boundary impedeance and in the second one i have to mesh the absorbant material also.. now i have a rough idea how to do the first step..coz the absorptivity of the material is provided ...
Hi all,
I wanted to ask .. how to model an absorbent material in FE? i mean i am trying to build a simple FE model in Matlab and i have a simple cylinder with a force input from a piston at one end and a rigidly backed abosrbent material at the other. the thickness of the absorbent material isnt...
