Date: Fri, 22 Oct 2004 10:07:03 -0400 (EDT)

Author: "Jason St. John"

Subject: Re: ping-pong ball/ Bernoulli effect demo

Post:

There's the Venturi apparatus, whic really does compare pressures along a
tube of nonconstant but smoothly-changing cross-sectional area. The
reason so many Bernoulli-like demos are not correctly explained by
Bernoulli effect is that they allow significant vortices to play a role,
and dissipative forces, I suppose, since Bernoulli's Law is really about
conservation of energy.

-jmsj
____________________________________________________
Jason St. John 617.353.5980 stjohn@bu.edu
Boston University Physics Department
Room 255, 590 Commonwealth Ave. Boston, MA 02215

On 2004-10-22.08:14 owner-tap-l@listproc.appstate.edu sent:

So what do we like as strictly (if there are any) Bernoulli demos?

tap-l@listproc.appstate.edu wrote:

> Richard Berg wrote:
>
>
> > Perhaps it should be pointed out that this demonstration does not show the
> > Bernoulli effect. Levitation, the curve ball, the Flettner ship, the
> > airplane wing, etc. are NOT examples of the Bernoulli effect.
> > Interesting, yes, but ....
> >
> > Dick Berg
> >
> > ***********************************************************************
> > Dr. Richard E. Berg, Professor of the Practice
> > Director, Physics Lecture-Demonstration Facility
> > U.S. mail address:
> > Department of Physics
> > University of Maryland
> > College Park, MD 20742-4111
> > Phone: (301) 405-5994
> > FAX: (301) 314-9525
> > e-mail reberg@physics.umd.edu
> > www.physics.umd.edu/lecdem
> > ***********************************************************************
> >
> >
> actually about 20% of a wings lift is due to the Bernoulli effect, if
> you wish to think of it that way,
> cheers,
> David
> P.S. the other 80% is due to the "angle of attack" of the wing.
> P.P.S. so why does a curve ball curve, Dick?
>
>
> .

From Gerald_Zani@brown.edu Fri Oct 22 10:09:01 2004

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