Re: KRS lake

From: Seppo Renfors (Renfors_at_not.com.au)
Date: 08/10/04 

Date: Tue, 10 Aug 2004 14:25:21 GMT

Eric Stevens wrote:
>
> On Tue, 10 Aug 2004 02:17:24 GMT, Seppo Renfors <Renfors@not.net.au>
> wrote:
>
> >
> >
> >Eric Stevens wrote:
> >>
> >> On Mon, 09 Aug 2004 08:01:06 GMT, Seppo Renfors <Renfors@not.com.au>
> >> wrote:
> >>
> >> >
> >[..]
> >> >Actually that is a contradiction - "shallow" is slow (for the same
> >> >slope) due to friction (drag) which increase by the square of the
> >> >increase in speed. But even then it isn't that simple as the rate of
> >> >flow varies from top to bottom and side to side with a laminar flow.
> >>
> >> See
> >> http://services.eng.uts.edu.au/~simonb/jayas%20hyd%20web%20page/Momen.pdf
> >> for an explanation which is almost certainly above your head (as per
> >> the deep slow flow :-).
> >
> >If you can't even fathom the issue, don't bother replying with
> >irrelevant material. The issue has nothing at all to do with hydraulic
> >jump, high jump, long jump or even your jumping to conclusions!
> >
>
> This is what you said originally:
>
> " I don't think that is true at all. Water flows at a constant rate
> irrespective of slope. Think of it this way, a steep descent that
> levels out to a near flat surface. A river that starts on that
> slope would "back up" when it hit the near flat surface and block
> the flow, would it not IF your argument "held water" so to speak"
>
> That was the point I was addressing. The river certainly "backs up"
> but it does not block the flow. It merely changes from fast-shallow
> flow to slow-deep flow with the point of change marked by a hydraulic
> jump of one kind or another.

Oh, for christ sake Eric - Note I used the words "block the flow".
The term "backs up" as understood from the context, specially in
quotation marks, is in the same sense a blocked toilet "backs up". It
is *NOT* a "hydraulic jump" which is completely irrelevant as your
story dealt with a tidal wave moving up-river. Such does not exist in
this case. Further to that, the point YOU entered the discussion it
had moved on to a specific example which you replied to and NOT the
bit you quoted. This is the text YOU responded to:

"Aha.... so explain a steep slope followed by a shallow slope with the
same channel cross section. The water still has to flow at the same
rate (volume/minute) irrespective of the slope, doesn't it. Therefor
it follows that the slope is not a factor in the speed of water flow.
A channel roughness does have a bearing on it."

NOTE: There is no longer a single mention of "backs up" at all.

NOTE: I specifically state "same channel cross section" - which is
promptly ignored in your reply.

NOTE: It deals also with channel roughness - a factor governing the
speed the flow will be at. In reply to the issue of channel roughness
you AGAIN posted about "hydraulic jump".... pffffttttt......

NOTE: I specifically gave an example of a VERY flat river that flowed
VERY fast in the text following my quoted text above. This too was
ignored.

I recall reading about this some while ago, but can't recall exactly
what it was now and I may not have the answers to this at present
anyway, I may even remember it completely wrong - but I still
recognise flim-flam when I see it. Even IF you can describe an effect
at the change of slope with your term, it is NOT relevant to the issue
- it doesn't CAUSE anything related to the issue. 

-- 
SIR - Philosopher unauthorised 
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The one who is educated from the wrong books is not educated, he is
misled.
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