Re: Fwd: Mosquito Flight

[Brian Whatcott <betwys1@SBCGLOBAL.NET>]

This note had a certain haunting quality for me.
Lifted from the average physics book? Possibly not.
This was a modeling exercise, from my vantage.
I was sorry no one took the bait or played with it.

I saw that given the sound intensity and the distance from the
compact emitter, one could find a number for the total acoustic
power available.

I saw that given the macro-photo, one could estimate the weight and
the wing area of the crittur.
I don't recall seeing mosquito hovering flight visualized ever, so I
needed to substitute for the mind's eye, the numerous beautiful
movie shots that capture humming bird hovering flight in slo-mo:
wings rotating half a revolution on a vertical axis, in contra-rotation.

The wings support the weight of course: an estimate for equivalent
wing pressure could be found: the sound frequency sets the rotation
speed of the wings - the tip speed can be estimated.

At this point one could come up with expressions for total sound power
and  some expression for the product of wing pressure squared and
particle velocity [I take it] times some coupling factor to get an
independent value for sound power.

 And that was as far as the puzzle would take me.
I wonder what the students made of it?

Brian W

At 11:54 AM 2/14/2004, dan mac isaac  forwarded this message:

> > From: Raacc@aol.com
> > Date: February 13, 2004 10:43:56 PM EST
> > To: Dan.MacIsaac@NAU.EDU
> > Subject: Mosquito Flight
> >
> > Dan,
> >
> > I'm not a member of phys-l, but do read the posts.
> >Here's a problem I gave to my students and thought it might
> > be of interest to the list.  A picture of the mosquito is at:
> >
> >   <http://members.aol.com/raacc5/prob.htm>
> >
> >  The picture shows a mosquito with the torso dimensions of
> >6 mm.   Assume the density of the mosquito is that of water.
> > Given that the mosquito beats its wings at 500 Hz, and the
> >sound level is 40 dB at one meter, find a model for a
> >hovering mosquito that is consistent=
> > with these experimental parameters.
> >
> > Bob Carlson
> >
> Dan MacIsaac, Assistant Professor, Physics, SUNY Buffalo State Colleg=
> e
> 222 SCIE BSC 1300 Elmwood Ave, Buffalo NY 14222 716-878-3802
> <macisadl@buffalostate.edu> <http://PhysicsEd.BuffaloState.edu>


Brian Whatcott    Altus OK    Eureka!