Theory on lift
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The natural tendency for any locally derived and accelerated gas path that must re-enter a still mass is to curve. This does not apply to an energetic path that is parallel the direction of entry of the wing. . .
As the upper biased flow spills off the tip, it curves, and contacts the flow off the bottom, which is curving also. The two flows are discrete, and compliant with Newton (#2), wish to maintain their cross section shape. There is no choice for them but to entwine....(Bernoulli, as matchmaker). Unbound, they expand, whilst gradually losing definition, and eventually all memory of their originating shape.
Will that suffice for a description of vortex generation via the Oxford genius?
I thought not. Anything at all useful?
As the wing collects, contains, and deflects (directs) air, can we then call it a 'nozzle'?
As the upper biased flow spills off the tip, it curves, and contacts the flow off the bottom, which is curving also. The two flows are discrete, and compliant with Newton (#2), wish to maintain their cross section shape. There is no choice for them but to entwine....(Bernoulli, as matchmaker). Unbound, they expand, whilst gradually losing definition, and eventually all memory of their originating shape.
Will that suffice for a description of vortex generation via the Oxford genius?
I thought not. Anything at all useful?
As the wing collects, contains, and deflects (directs) air, can we then call it a 'nozzle'?
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GREEK LETTERS
Originally Posted by Owain Glyndwr 14. nov 2012 21:51
Capital Gamma (sorry I can't find a way of inserting the Greek letter)
OwainGlyndwr , OWAIN GLYNDWR
Method :
Oh! Sorry ! I was still writing with greek letters ! 
Method:
Use free Open Office,
select latin letter, write in latin letters, for instance Arial Police
select greek letter, write in greek letters, for instance Symbol Police
Select the mixed lines with as well latin and greek letters
Copy
Paste in PPRuNe Reply !
Add your PPRuNe's smilies as needed ..
Last edited by roulishollandais; 16th Nov 2012 at 14:30. Reason: reread and add spaces if needed
Moderator
For occasional special characters, if you are using a Microsoft installation, you might try the character applet which gives you access to the complete character set for each font installed .. eg on my installation this is at
Windows\System32\charmap.exe
ie including all the non-keyboard characters ...
I have used the program on each Windows version and the filename has always been charmap so it ought not to be too difficult to find on any installation.
If you know the key combinations, characters can be entered directly but charmap is great for lazier folks like me.
Windows\System32\charmap.exe
ie including all the non-keyboard characters ...
I have used the program on each Windows version and the filename has always been charmap so it ought not to be too difficult to find on any installation.
If you know the key combinations, characters can be entered directly but charmap is great for lazier folks like me.
We could make it easier....anyone care to explain why water flowing down the plug hole always forms a vortex ? If we can't answer that, not a lot of hope for us......
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Manhole covers are always round.
Nature hates a corner.
Viscosity.
Rate.
"if instead of fluid, the medium was ball bearings, would there be a vortex at the drain?"
Transition.
Nature hates a corner.
Viscosity.
Rate.
"if instead of fluid, the medium was ball bearings, would there be a vortex at the drain?"
Transition.
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They are round because it is the only shape that will not fall into the hole after removal.....
This suggests that Nature is economical, and efficient.
A ninety degree turn in a pipe is wicked drag, hence "elbow" or, camber.
I am trying to evolve an explanation for vortex, and I am not there yet.
Part of it has to do with the containment of energy in "shape", and least drag.
By the way, the vortex forms only within two limiting considerations. Pressure and Volume. I think. So that introduces "locality" (proximity). And 'locality' has to do with the point at which volume and Pressure are interchangeable as to effect, I think.
'Rate' is the bottom line for any Physics problem, imo.....
This suggests that Nature is economical, and efficient.
A ninety degree turn in a pipe is wicked drag, hence "elbow" or, camber.
I am trying to evolve an explanation for vortex, and I am not there yet.
Part of it has to do with the containment of energy in "shape", and least drag.
By the way, the vortex forms only within two limiting considerations. Pressure and Volume. I think. So that introduces "locality" (proximity). And 'locality' has to do with the point at which volume and Pressure are interchangeable as to effect, I think.
'Rate' is the bottom line for any Physics problem, imo.....
Last edited by Lyman; 17th Nov 2012 at 15:56.
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Vortices and principles of lift - all closely related.
Helmoltz's Theorems apply to inviscid flows and where the influence of viscous forces are small enough to be ignored.
Helmoltz's Theorems apply to inviscid flows and where the influence of viscous forces are small enough to be ignored.
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Thank you John!
Rh
in Windows
demarrer
executer
charmap.exe
OK
in charmap array
stay in your police for instance arial
for any character of your string for instance : capital gamma,alpha,mu,mu,alpa selectionner
at the end of the string : copier
in PPruNe reply
coller
Result :
Γαμμα
Rh
in Windows
demarrer
executer
charmap.exe
OK
in charmap array
stay in your police for instance arial
for any character of your string for instance : capital gamma,alpha,mu,mu,alpa selectionner
at the end of the string : copier
in PPruNe reply
coller
Result :
Γαμμα
Last edited by roulishollandais; 17th Nov 2012 at 18:29. Reason: add test charmap.exe on Windows
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@jt
Yes thanks for that John. I was OK with symbols using copy and paste and Word or similar, but I was trying to do it directly using the fonts available inside PPRuNe edit text function.
Could something suitable be added perhaps?
OG
Yes thanks for that John. I was OK with symbols using copy and paste and Word or similar, but I was trying to do it directly using the fonts available inside PPRuNe edit text function.
Could something suitable be added perhaps?
OG
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Originally Posted by Mr Optimistic 17th Nov 2012 16:19
We could make it easier....anyone care to explain why water flowing down the plug hole always forms a vortex ? If we can't answer that, not a lot of hope for us......
Feigenbaum unified them. He met Libchaber who has got very famous for his two little vortex in a small box of helium...
Albert J. Libchaber - Wikipedia, the free encyclopedia
rh
Last edited by roulishollandais; 19th Nov 2012 at 15:36. Reason: two time Libchaber wiki ref
IIRC it is simply that any existing rotation in the water amplifies due to the small size of the outlet compared to the radius of the bath tub thus increasing the rate ot rotaton when approaching the outlet.
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Before there is motion, there are waves. The waves begin at the aperture, they cannot begin in the fluid. At the smallest disturbance in the energy field, there is an angular imprint on the soon to be vortex, an imprint that detemines the poles of the filaments. The angular disturbance is the instigator of the spin of the vortex.
Are you certain this is unrelated to the Gravitational field spinning between two poles?
Water waves react to frequency and amplitude, plus direction?
Only if the Earth was not spinning would gravity be acting ninety degrees to the center, it us always either 90+/-. There is no thing such as 0 rate in our system.
Everything is always moving, and direction is spin dependent, I think......in a passive locale. (tub, drain, water,)
Are you certain this is unrelated to the Gravitational field spinning between two poles?
Water waves react to frequency and amplitude, plus direction?
Only if the Earth was not spinning would gravity be acting ninety degrees to the center, it us always either 90+/-. There is no thing such as 0 rate in our system.
Everything is always moving, and direction is spin dependent, I think......in a passive locale. (tub, drain, water,)
Last edited by Lyman; 19th Nov 2012 at 00:39.
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Last edited by HazelNuts39; 19th Nov 2012 at 09:45.
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HazelNuts39
Now we're talkin'! So coriolis can be abandoned since it has "minimal effect".
Conditions must be established to allow it to obtain!
Imagine instead of the standard (typical) airfoil section in the bernoulli model, something different.
Rather than fix the wing at 0 degrees, and provide airflow other than from the motion of the airfoil, let us mount the wing on a spar pivot. The wing can now rotate on command, independent of flow; Angle of Incidence can be controlled.
Let us set 90 degrees, 'flat plate'. We now activate the tunnel turbines, to 200 knots. Without delay, we immediately select and acquire 8 degrees of AoI.
Where did 'Kutta' go?
I envision this experiment as analogous to the lack of coriolis effect in Bermoulli's bathtub.
I think my point is to establish that given a set of "prescribed" conditions, just about anything can make sense, or fail explanation.
How obsessively we unpack the theory of lift requires a man made set of conditions?
A famous aviator has demanded that the shape of an airfoil must be a cambered one, to explain lift. He is not WRONG. Not exactly.
The rotation of a vortex aft of the moving wing tips is predictable, due the architecture of the wing, and has immutable direction. This is to do with velocity and viscosity, plus existing flow.
Once established, prior conditions create a rigid and predictable result.
In reality, and in fantasy, both.
To disprove the bathtub problem, actual conditions must be explained, then accounted for. Does this make the standard bernoulli myth accurate?
Isn't "Suction" yet another mistake?
Now we're talkin'! So coriolis can be abandoned since it has "minimal effect".
Conditions must be established to allow it to obtain!
Imagine instead of the standard (typical) airfoil section in the bernoulli model, something different.
Rather than fix the wing at 0 degrees, and provide airflow other than from the motion of the airfoil, let us mount the wing on a spar pivot. The wing can now rotate on command, independent of flow; Angle of Incidence can be controlled.
Let us set 90 degrees, 'flat plate'. We now activate the tunnel turbines, to 200 knots. Without delay, we immediately select and acquire 8 degrees of AoI.
Where did 'Kutta' go?
I envision this experiment as analogous to the lack of coriolis effect in Bermoulli's bathtub.
I think my point is to establish that given a set of "prescribed" conditions, just about anything can make sense, or fail explanation.
How obsessively we unpack the theory of lift requires a man made set of conditions?
A famous aviator has demanded that the shape of an airfoil must be a cambered one, to explain lift. He is not WRONG. Not exactly.
The rotation of a vortex aft of the moving wing tips is predictable, due the architecture of the wing, and has immutable direction. This is to do with velocity and viscosity, plus existing flow.
Once established, prior conditions create a rigid and predictable result.
In reality, and in fantasy, both.
To disprove the bathtub problem, actual conditions must be explained, then accounted for. Does this make the standard bernoulli myth accurate?
Isn't "Suction" yet another mistake?
Last edited by Lyman; 19th Nov 2012 at 15:56.
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In France many strange things are told about creationists schools...
Some of you perhaps were in such schools ?
A strange ref too, but correct, with bifurcation :
Mitchell Feigenbaum - Wikipedia, the free encyclopedia
Agreed !
Some of you perhaps were in such schools ?
A strange ref too, but correct, with bifurcation :
Mitchell Feigenbaum - Wikipedia, the free encyclopedia
Originally Posted by mm43
Worth changing the font to Georgia or Palatino (serif). It will look better!
Γαμμα
Γαμμα
