Quote:
Originally Posted by
JayPee
Please, copy and paste your exact question.
I am currently testing the Soundflow software and am so far very
impressed. I have a question regarding the Absorber density (optional)
setting.
In the manual it states:
When the FLOW RESISTIVITY is specified, the ABSORBER DENSITY can be
entered optionally. If the latter value is given, additional effects due
to the
conduction of sound by the vibrating structure are included in the result.
However, this should account for a small correction only, otherwise the
plate
or perforated panel type should be used for the material.
Can you clarify what would be considered a "small correction"?
For example if modelling a slat resonator, the density setting can have
a drastic effect on the centre frequency of absorption. In the attached
images you can see that adjusting for density the centre frequency drops
more than 100Hz. I have been unable to find any literature theoretical
and measured that show such a dramatic centre frequency shift with the
addition of absorption to a Helmholtz system. Is this a case where
density should not be used and only Flow Resistivity entered?