resonant frequency ?

[johnab]

The resonant frequency of helmoltz resonator, f = c/2*3.14 (A/VL)^.5 Where A is surface area & V is the cavity volme & L is the effective length.

My question is does it make a difference for Transmission loss/tuning of the system if use circular, or any other cross section like square with circular end for the connecting pipe of helmoltz by keeping same surface area?

As per above formula I don't see it but appreciate if someone have different experience.

 

[GregLocock]

You might need a correction for A if you go to some crazy shape that causes lots of drag, and the end correction for L will not be the standard figure either.

But it will still work, just at adifferent frequency.

Square vs circular probably would make no difference that is measurable.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Rob45]

That formula that you're using was derived from differential equations assuming a circular cross-section throat and a circular cross-section cavity having I believe a length the same order of magnitude as the diameter. When you stray very far from those simplifying assumptions, as Greg said some correction will be required, but it will still function.
Just assume that testing will be required to validate the design before you go into production!