Re: Bernoulli's equation

[John Mallinckrodt <ajmallinckro@CSUPOMONA.EDU>]

On Thu, 10 Jan 2002, Bob Sciamanda wrote:

> If I read correctly, we have a pipe narrowing followed by a
> pipe enlarging.  At each junction there is a pressure gradient
> - a pressure drop at the first junction (where the fluid
> speeds up), and a pressure rise at the second junction (where
> the fluid slows down).  I assume a left to right flow
> direction in your diagram. What's the problem?

Perhaps I misunderstood the point of your previous message. I
thought you were implying that the pressure is large upstream from
an obstruction and that it is, in fact, *made* large *because* of
the obstruction. If so, that might seem to rule out having the
pressure become large again after it passes the last obstruction.

Part of the point of my posed problem was to make it clear that
one need not make any assumption about the direction of flow in
order to answer it.  I notice that you did make such an
assumption, but I'm sure you will agree that it is irrelevant.

John Mallinckrodt      mailto:ajm@csupomona.edu
Cal Poly Pomona          http://www.csupomona.edu/~ajm