Date: Wed, 17 Nov 2004 08:34:33 -0500

Author: Chuck Britton

Subject: Re: Bernoulli vs Coanda demo


Can/would someone estimate the Reynolds number for a breath of fresh air??

Does Coanda 'explain' the lift of a strip of paper held o the lower
lip while blowing. or the 'lift' for the convertible rag-top?

At 8:11 AM -0500 11/17/04, Wolfgang Rueckner wrote:
>I agree. Elegant and thought provoking. Nice piece of work -- Wolfgang
>On Nov 17, 2004, at 6:58 AM, Zani, Gerald wrote:
>>That is excellent! It is elegant and simple. A good entry for the
>>apparatus competition.
>>It is important to keep the chat flowing about Coanda versus False
>>Bernoulli so that it will be more familiar to all.
>>If the same demo were made to hook up to the faucet and work with a
>>water stream rather than an air stream it could prove that the
>>fluid compressability is important.
>>Jerry Z.
>>From: on behalf of John Welch
>>Sent: Tue 11/16/2004 7:27 PM
>>Subject: Bernoulli vs Coanda demo
>>Hi all -
>>I've been getting into the 'False Bernoulli' stuff lately, and I
>>just made a demo that illustrates things pretty well, I think. It
>>is a manometer with 3 tubes, one with a flat surface on top, one
>>with a concave, and one with a convex surface. The pressure in a
>>stream of air blown over them is the same as, more than, and less
>>than atmospheric pressure, respectively. I'm going to ask students,
>>who have been told that "A fast moving stream of air has less
>>pressure than the stationary air around it", to predict what will
>>happen in this demo, and use the results to initiate a discussion
>>of the flawed explanation. The Coanda effect seems to more
>>correctly predict the results.
>>You can see a picture of this demo at:
>>Thanks to everyone who has contributed to the discussion of this
>>common error.
From Wed Nov 17 09:24:37 2004