Jump to content
Mander Organ Builders Forum

Wind Trunks


David Coram
 Share

Recommended Posts

I recently made the assertion to a friend that his wind system - consisting of perfect square wind trunks, about 100mm x 100mm, with 90 degree corners - could be improved by converting it to oblong sections with staggered corners.

 

The system as it stood produced a lot of static wind noise and a good deal of instability, particularly at the start of pipe speech.

 

I have read somewhere (lots of places, actually) that wind will try and go down a channel in a cyclone, like water going down the bath plug; if you give it a square to go down, this will leave "empty" corners which will resonate and cause noise. With an oblong, I believe this does not happen and the wind is forced to travel in a straight line because there is insufficient height in proportion to width for it to turn into a cyclone.

 

The point about corners needing to be created from 2 or 3 lesser-angled pieces, rather than just a single 90 degree joint, seems a fairly obvious one. Anyone who has stood on the corner of a narrow street on a windy day will know that wind doesn't go round tight bends without lots of disturbance and fluctuation in pressure.

 

Trouble is, when I come to try and defend my position, Google can not supply a single piece of documentary evidence. Does anyone know of any articles that prove or disprove what I'm saying? I had a feeling that there was a Fisk article about this, but I can't find it...

Link to comment
Share on other sites

You want to look at articles relating to fluid flow in pipes. There are basically two types of flow; Laminar and Turbulent. Laminar flow gives the smoothest delivery of fluid (air is classed as a fluid). Sharp changes of (pipe) direction will lead to Turbulent flow. This will lead to an un-smooth delivery of fluid. This is normally undesirable in hydraulic and pneumatic applications.

 

Hope this helps. B)

Link to comment
Share on other sites

Google can not supply a single piece of documentary evidence.  Does anyone know of any articles that prove or disprove what I'm saying?  I had a feeling that there was a Fisk article about this, but I can't find it...

 

=====================

 

It possibly has no relevance to organ-building, but using a vortex tube in a windflow, can speed up the movement of a gas to around the speed of sound!

 

Funny things vortices, and almost impossible to predict accurately.

 

I'm sure the Fisk article is there somewhere....I may have something on disc....I'll check.

 

MM

Link to comment
Share on other sites

I have read somewhere (lots of places, actually) that wind will try and go down a channel in a cyclone, like water going down the bath plug; if you give it a square to go down, this will leave "empty" corners which will resonate and cause noise.  With an oblong, I believe this does not happen and the wind is forced to travel in a straight line because there is insufficient height in proportion to width for it to turn into a cyclone.

 

The point about corners needing to be created from 2 or 3 lesser-angled pieces, rather than just a single 90 degree joint, seems a fairly obvious one.  Anyone who has stood on the corner of a narrow street on a windy day will know that wind doesn't go round tight bends without lots of disturbance and fluctuation in pressure.

 

Trouble is, when I come to try and defend my position, Google can not supply a single piece of documentary evidence.  Does anyone know of any articles that prove or disprove what I'm saying?  I had a feeling that there was a Fisk article about this, but I can't find it...

 

 

 

 

====================

 

Well, you could enjoy a little light reading on the subject to start with. B)

 

http://en.wikipedia.org/wiki/Vortex

 

Having first understood all that, you might then like to consider the phenomenon known as "Fan Death".

 

This is where air is sucked out of a room by a fan, and the unfortunate victim suffocates.....there is a website <www.fandeath.net> :(

 

Others believe that fans split up the molecular structure of air particles, and the air then become unbreathable......again you suffocate. :(

 

Apparently, the Koreans swear that fan-death really happens. :)

 

MM

Link to comment
Share on other sites

I have read somewhere (lots of places, actually) that wind will try and go down a channel in a cyclone....

 

 

 

======================

 

I've just had a brain-storm!

 

Why don't organ-builders use cyclonic-separation in organ winding systems?

 

This is the principle of the Dyson vacuum-cleaner, which uses a conical inlet and a vortex chamber, making the air swirl around at high-speed; thus throwing heavy dust and grit particles to the outside of the chamber, where it can be collected and removed safely and cleanly without recourse to filters.

 

This way, organs would be kept as clean as a new pin inside the windways and chests, and any cleaning would be restricted to readily removable pipework.

 

Oooops!

 

Coming to think of it, that would put a lot of organ-builders out of work. Cleaning is such a good way of improving cash-flow.

 

MM

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...