sound radiation efficiency?
sound radiation efficiency?
(OP)
when i use BEM in sysnoise(rev5.6) to compute the sound radiation efficiency of a cylindrical shell with two end plates in water, i found the efficiencies at several frequencies are negative. can anybbody help me to explain it.thanks!





RE: sound radiation efficiency?
This is a real world effect if you plot the intensity around an engine - in the near field some parts of the engine absorb energy while others emit it at the same frequency.
My explanation for this is that the far-field response is essentially that of a point source, so we have to resolve the vibrations of the rather strangely 'shaped' source into a spherical wavefront. The system does this by shuffling energy behind the wavefront.
If that explanations helps, terrific. If it is right, even more terrific.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: sound radiation efficiency?
are there anybody who are familiar with sysnoise and tell me the method to solve this problem?thank you very much!
RE: sound radiation efficiency?
RE: sound radiation efficiency?
On reflection I agree with your previous comment, radiation efficiency should always be positive.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.