Quote @ peeplj
Jim, that’s just a myth! Playing recorder doesn’t make you go blind, either.
Playing recorder is a normal, healthy solitary activity…it’s just something we do in private because often we find nobody really wants to see or hear us do it. Most musicians don’t admit it, but polls tell us almost everybody does it.
Cranberry, you are a scream!!!
AAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRRRRRRGGGGGHHHHH!!
serpent
Hi Steven
For those with physics in mind…
http://www.phys.unsw.edu.au/~jw/fluteacoustics.html
As a “Laymans Explanation” for how a whistle embouchure works…
Air is compressed into “Semi-Laminar Flow” by the decreasing windway, it then passes out of the windway and across the open “window” to strike just above the lip of the Labium Ramp. This causes a vacume or “siphon effect” just below the window. As this internal vacume increases, air begins to rush up the resticted bore, from the bottom(or nearest open tonehole), to fill this vacume.
When the leading pressure wave from the inrushing air reaches one quarter of the way up, the vacume below the window becomes so great that it pulls the airstream down into the whistle and under the lip, quickly filling the vacume and then compressing the air under the window.
The resulting pressure wave rebounds off the fipple face and is sent down to meet the inrushing wave at the halfway point. The opposing pressure waves rebound off each other and the returning upper wave pushes the windway airstream back out/above the lip to start the cycle all over again.
It lacks finesse, but it is accurate. Help me out guys, have I missed something?
T.H.
Ok, here’s my take on this. First of all, the airflow in the windway is not laminar - the Reynolds number is too high. What you have in a whistle is a turbulent jet of air coming out of the windway and into the relatively stagnant air in the window area. Any jet of fluid (and yes, air is a fluid) entering a stagnant fluid will set up a alternating series of eddies called a Von Karman street (why it’s called a “street”, I have no idea). The frequency of these eddies is determined by the Strouhal number. As these eddies hit the blade, the eddies on the bottom of the blade temporarily increase the pressure, and when the eddies are on top of the blade, it decreases the pressure. This is what leads to the “edgetone”. The edgetone increases with increasing velocity of the jet.
A pipe, however, can’t vibrate at all of those frequencies, because it is a tuned cavity. When the edgetone is some multiple of the pipe frequency, then the pipe vibrates and the whistle sounds. If you blow harder, the edgetone goes up and eventually the pipe jumps to the next octave.
For more on this check out:
http://www.nmol.com/users/wblocker/
D