UVMFLOWNET Archives

October 2012

UVMFLOWNET@LIST.UVM.EDU

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Don Ridgway <[log in to unmask]>
Reply To:
UVM Flownet <[log in to unmask]>
Date:
Tue, 30 Oct 2012 22:04:23 -0700
Content-Type:
text/plain
Parts/Attachments:
text/plain (23 lines)
I got asked an awkward question by a student today, regarding the Reynolds equation:

Re = V p 2r
            n

My primitive school email access won't allow me to make that lower-case p into a rho for density, nor that lower-case n into an eta for viscosity, but you get the idea.

The question was this: since we know from another equation—Q = V x CSA—that a reduction of cross-sectional area means an increase of mean velocity, then why don''t those two balance out in the Reynolds equation?

For example, if the radius is doubled, won't that bring about a decrease to 1/2 of the velocity, leaving Re unchanged?

My clever response: life is complicated. And I'll get back to you.

I'm obviously angling for a bit of perspective from Dr. Beach from up there in Seattle (whence I'm flying Friday, as it happens).

Thanks in advance to anyone with help on this.


Don Ridgway

To unsubscribe or search other topics on UVM Flownet link to:
http://list.uvm.edu/archives/uvmflownet.html

ATOM RSS1 RSS2