Unusual resonance behaviour?

Tried posting this to a physics newsgroup, but haven't gotten a reply yet. Thought it might be more productive to post here...

I'm studying a resonant system in which the peaks over a wide range of central frequencies are well-fitted by a Lorentzian with a width (gamma) proportional to the square root of the central frequency -- or, equivalently I suppose, a resonance with a quality factor also proportional to that square root.

Does anybody have any experience with resonances of this form? I've been trying to understand what it says about the nature of the resonance, but haven't managed much.

Reply to
jcooper
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I'll discuss ideas, but I don't think I have much insight to offer. A Q which rises with frequency suggests a system which is lossier at low Fx, and better at high Fx Losses usually rise with Fx, so this is atypical behavior.

Rather than an oil pot damper model, this would be something like a thixotropic fluid pot damper - or a system with a high pass filter in the loop possibly?

There you have it: I batted the idea around, but nothing useful poopped out

sorry!

Brian Whatcott Altus, OK

Reply to
Brian Whatcott

It's interesting that you say this is atypical. My understanding was the LRC circuits, for instance, have Q proportional to f, with some systems ("hysteric damping", as I recall) giving Q proportional to f^2.

The high-pass filter, however, is a very interesting idea. Would I be safe to say that, at the least, Q proportional to the square root of f is not outright absurd?

Reply to
jcooper

snipped-for-privacy@ucalgary.ca wrote in news: snipped-for-privacy@o13g2000cwo.googlegroups.com:

I wonder if a metal panel, air damped, above coincident frequency, might exhibit that sort of behaviour. As the modal density increases the effectiveness of the panel at pumping air will drop off, reducing the damping somewhat.

Is this over a restricted frequency range, or from 0 to infinity (and beyond)?

Cheers

Greg Locock

Reply to
Greg Locock

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