Designing a resonance tube with a defined ambient wind speed

AI Thread Summary
The discussion focuses on designing a resonance tube that resonates at a wind speed of 4 mph (1.78 m/s). The original poster seeks assistance in determining the relationship between wind speed and resonance frequency, acknowledging their understanding of resonant frequency but lacking clarity on the necessary equations. Participants suggest referencing existing literature on wind instruments, particularly the work of Ising, and highlight the importance of air consumption rates in instrument design. They note that typical blowing pressures for instruments like recorders and organs are significantly higher than the desired wind speed, indicating potential challenges in achieving the desired resonance. Overall, the conversation emphasizes the complexity of adapting existing theories to new designs in wind instrument acoustics.
AuroraIndust
Messages
11
Reaction score
0
Hello,

As we know, when you blow over the neck of a bottle, it resonates at a certain frequency.

I want to build a cylinder that will resonate at a certain wind speed: 4 mph or about 1.78 m/s

I definitely know how to find the resonant frequency of a cylinder. However, I'm not sure what equation would help me solve for finding what "wind speed" over the top would cause it to resonate!

What am I missing here? Is this a more difficult problem than I anticipate?

Thanks!
 
Physics news on Phys.org
People have been designing wind instruments empirically for thousands of years, but it seems that a theory of what works and what doesn't was first published only in 1971!

The original paper is in German and is about organ pipes, so the geometry isn't exactly the same as your situation, but here's a reference to a (very short) summary in English: http://www.mmdigest.com/Tech/isingform.html

If you investigate how well this works for bottles, you will probably be doing some genuinely original research.
 
Do you know what Q, the "Air consumption rate" might be referring to? I don't see where any air is being "consumed".

I can find the pressure of the air at the open end of the cylinder, and I know the pressure at the bottom of the cylinder. Assuming I know those and several other things I should be able to calculate what size/volume tube will work, right?

If someone can assist me in adapting this (http://www.mmdigest.com/Tech/isingform.html) to work with my situation, that would be much appreciated. As I can not figure out a way...

Thanks for any help!
 
An organ pipe (or a recorder, for that matter) needs air blown into it: Thats your air consumption rate.
Are thinking of something like a a pan flute?
You can find a lot of information and details in Fletcher/Rossing, The physics of musical instruments.
And if my experience with instruments is not totally off: I don´t think you can make a speed detector out of a flute, and 2m/sec is far too slow.
Recorders need a blowing pressure of a few cm water gauge; organs are nearer to 10cm. (Transverse) flutes are not much different.
1cm water gauge = 100Pa => ~13m/sec

In the link, Walcker is a german organ builder and Hausmitteilung is "internal communication". I´m sure you can find the articles by Ising elswhere
 
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top