Subject: Re: why the sugar in the tea cap, consntrate in the middle
From: schoon@na.chalmers.se (Johannes Schoon)
Date: 25 Oct 1996 08:18:31 GMT
Carmon Tal (tal) wrote:
: when you stir tea with sugar , the sugar consentrate in the middle of the cap ,
: while some of us may expect the centrifugal acceleratin to push it in a
: direction opposite to the center of the vortex (the sugar is heavier than
: water)
: may you have the answer?
This is almost the classical text-book illustration of secondary
flow. (Usually, small specks of tea leaves are considered, since sugar
has a tendency to disappear :-) )
Most of the tea will rotate, as stirred, in the cup. Close to the
bottom of the cup, however, there will be a boundary layer with tea
that move as fast. The tea-speeds become progressively lower, the
closer to the bottom of the cup we get.
Conclusion, the centrifugal acceleration on the tea close to the
bottom is much lower that on tea higher up.
The reason that tea in the boundary layer at the bottom - and small
specks of tea leaves with it - move inwards, is that the radial
pressure gradient that is produced by the swirling flow "survives"
throught the thickness of the boundary layer. That is, since the
balance between pressure gradient and centrifugal forces that we see
in the middle of the cup, has been upset by the boundary layer, the
fluid in it is pushed to the center by the pressure gradient.
Personally, I don't like explanations where the shape of the free
surface is used to explain the pressure gradient. It wouldn't help us
understand what happens in a cup with a lid. (There, we get a boundary
layer at the lid too, and there will be two secondary flows. Small
bubbles of air at the lid, will be swept to the center of the lid just
as tea leaves will be swept to the center of the bottom.)
Hope this was possible to understand.
--
Johannes Schoeoen
"master of research under the event horizon"
(No matter how much work you throw in, nothing ever comes out.)
dept. of Naval Architecture and Ocean Engineering
Chalmers University of Technology, Gothenburg, Sweden
Subject: Re: why the sugar in the tea cap, consntrate in the middle
From: kenneth paul collins
Date: Sun, 27 Oct 1996 01:23:58 -0500
Johannes Schoon wrote:
>
> Carmon Tal (tal) wrote:
> : when you stir tea with sugar , the sugar consentrate in the middle of the cap ,
> : while some of us may expect the centrifugal acceleratin to push it in a
> : direction opposite to the center of the vortex (the sugar is heavier than
> : water)
>
> : may you have the answer?
>
> This is almost the classical text-book illustration of secondary
> flow. (Usually, small specks of tea leaves are considered, since sugar
> has a tendency to disappear :-) )
>
> Most of the tea will rotate, as stirred, in the cup. Close to the
> bottom of the cup, however, there will be a boundary layer with tea
> that move as fast. The tea-speeds become progressively lower, the
> closer to the bottom of the cup we get.
>
> Conclusion, the centrifugal acceleration on the tea close to the
> bottom is much lower that on tea higher up.
>
> The reason that tea in the boundary layer at the bottom - and small
> specks of tea leaves with it - move inwards, is that the radial
> pressure gradient that is produced by the swirling flow "survives"
> throught the thickness of the boundary layer. That is, since the
> balance between pressure gradient and centrifugal forces that we see
> in the middle of the cup, has been upset by the boundary layer, the
> fluid in it is pushed to the center by the pressure gradient.
>
> Personally, I don't like explanations where the shape of the free
> surface is used to explain the pressure gradient. It wouldn't help us
> understand what happens in a cup with a lid. (There, we get a boundary
> layer at the lid too, and there will be two secondary flows. Small
> bubbles of air at the lid, will be swept to the center of the lid just
> as tea leaves will be swept to the center of the bottom.)
...in accord with your view, I see the centering behavior as the result
of a vortex... if one stirs one's tee hard, one can see the vortex... and
here's what's "weird": I expect that the formation of such confined
vortices will, one day, lead to what's referred to as "gravity" being
reformulated in terms of what's described by 2nd Thermo (WDB2T)...
the view, here, is that what's been referred to as "gravity" is actually
due to a =differential= flow of energy that's correlated with the
sustaining of what have been referred to as "atoms"... in this view,
"atoms" are spherical standing waves (SSWs) that are in
"compression"-"expansion" harmonic interaction with an flowing(!)
aether-like universal energy supply (UES)... SSW<->UES harmonics...
...the differential flow occurs because it requires work to sustain the
SSW<->UES harmonics, and this work shows up in the fact (in this view)
that, after doing the work necessary to sustain the harmonics, energy
radiates away from the "atoms" in the form of heat... 3.7k... the
post-sustenance order is less than the pre-sustenance order, and what's
been referred to as "gravity" is "just" this energy-flow differential...
matter just "goes with the flow"... and the flow goes to the center of
"mass" because centers of "mass" are the points at which the sustenance
of SSW<->UES harmonics is most-interferred with (due to all of the work
that's being done in sustaining all of the overlying "atoms")... so
that's where the energy-flow differential is greatest... so that
determines the direction in which matter "going with the flow" will
move...
...which brings us back to your tea leaves, Johannes, it's my view that
the vortices that form in teacups are actually "meters" which detect the
energy-flow differential that I've discussed here... the
boundary-layer stuff you cite is part of it... the vortex follows a
gradient with respect to energy's freedom to move... and that
gradient is asymmetrical with respect to centers of mass (Earth under
the teacup)... but not only that, the differential vortex formation
with different stirring vigor, nonlinearly discloses the differential
energy-flow that I discussed above... what I'm saying is that the "proof
is [not[ in the pudding", but in the tea... fluid dynamicists should
reify such connect-gravity-to-the-WDB2T-differential-flow "meters"...
such instruments will be of extraordinary importance with respect to
Unification in Physics... ken collins
_____________________________________________________
People hate because they fear, and they fear because
they do not understand, and they do not understand
because hating is less work than understanding.