Re: Midterm Question - Sort of

[William Beaty <billb@ESKIMO.COM>]

On Thu, 8 Jul 1999, Michael Edmiston wrote:

> Not only do all the instruments mentioned above work this way, it is
> also interesting to note there is an electromagnetic analog, and this
> is the klystron tube used to make microwaves.  In this case the
> standing electromagnetic waves in a cavity interact with a beam of
> electrons going past an opening into the cavity much like the air going
> over the opening of the pop bottle.

To build a "magnetron", we would make a tornado in a cylindrical box
(vacuum cleaner attached to the axis, with some tangential slot-orfices
around the rim of the box), and then jam a bunch of beer bottles through
the walls of the box with their mouths pointing inwards.  Adjust the
bottles so the wind across the bottle openings is at the proper angle to
generate a tone.  Turn it on and the racket should be impressive, like an
air-raid siren.  A multi-cavity resonant bottle-o-tron!

To complete the analogy, we could run a pipe through the wall of one of
the bottles in order to tap off some acoustic wattage without damping the
standing waves in the rest of the system.

:)

If the output of such a device was piped into a heavy-walled steel box, I
wonder if it would cook food via acoustic absorbtion?  What foods are the
best absorbers at about 1KHz?  Steamed buns?



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