Swept Volume Theory

Discussion in 'Hydrodynamics and Aerodynamics' started by Sailor Al, Aug 2, 2022.

  1. Sailor Al
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    Sailor Al Senior Member

    To stimulate further engagement with the topic, I have released a revised edition of my thesis. This new version highlights how employing an alternative frame of reference reframes the challenge from the domain of fluid dynamics to that of thermodynamics.
     
  2. C. Dog
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    C. Dog Senior Member

    I am noticing a lot of grammatical errors in mainstream media articles where homophones are dropped in out of context (too, two or to for example). It appears they use speech to text software that needs refining.
     
  3. Sailor Al
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    Sailor Al Senior Member

    The paper has been temporarily withdrawn for substantial enhancements and will be re-released shortly.
     
  4. CarlosK2
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    CarlosK2 Senior Member

    Paul Scott likes this.
  5. CarlosK2
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    CarlosK2 Senior Member

    But, but ...

    cherubs are male and seraphim are female (?)

    I don't know, I honestly don't know

    What I do know is that the young helmsman of the Hong Kong Admiral Cup team (1979) tried to go down a big Wave with the 46-foot Vanguard and capsized, doing a 360-degree flip.
     
  6. Sailor Al
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    Sailor Al Senior Member

    Hi Carlos. You are 100% correct in( 1), (2) and (3):
    There may be a positive over-pressure on the lower surface (1) providing the upward force or a negative over-pressure (under-pressure?) on the upper surface (2) providing an upward force, or a combination of both (3).

    But in (4) they do not work differently: the mechanism is the same in all three scenarios:
    Both the high pressure below and the low pressure above generate the same result:
    The net effect of the pressure differences will be an upward force on the plane that balances the effect of gravity on the mass of the plane.

    The $64 question is: what is the source of those pressure variations?
     
  7. CarlosK2
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    CarlosK2 Senior Member

    IMG20240723110548.jpg

    We divert a fluid, and by diverting a fluid (air, water or olive oil) a Force (F) is produced

    And some gentlemen in white coats arrive and analyze that Force (F) into two components

    Lift (L) and Drag (D)

    That's all

    The unfathomable enigma here is how a supposedly respectable magazine is capable of publishing such a childish article while the real world continues its inertial course

    It's quite disconcerting
     
  8. CarlosK2
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    CarlosK2 Senior Member

    Reflecting on this story on a large scale, one could conclude that a scientific community, a human group that talks to each other about their things, is ultimately and seen from the outside quite similar or equal to a tribe in the Amazon jungle.

    So the interesting thing about this story would be to investigate prejudices, group pressure and taboos.
     
  9. CarlosK2
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    CarlosK2 Senior Member

    Screenshot_2024-07-23-11-58-54-94.jpg

    -Very good; but do not escape from what interests us, we already know that the Wings of 2024 work on high pressure; but what interests us are the wings of 1914

    - Cherubs are they or are they not male ?

    - Answer without skipping

    - Well, the low pressure is maybe ultimately perhaps possible thanks to the viscosity of the fluid. Don't know. I don't understand this obsession with straining mosquitoes and swallowing camels
     
  10. CarlosK2
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    CarlosK2 Senior Member

    IMG_20240723_123921.jpg

    Why did Vanguard capsize when (1979) trying to ride down a wave driven by the powerful force of the earth?

    Because the band of rustlers (Yaw, Roll and Pitch) ... the shape of the bow and its Angle of Attack created a lot of high (H) pressure

    in addition low (L) pressure was created in the stern

    and on top of that the HydroDynamic center of the keel was forward of the center of gravity of the yacht
     
  11. CarlosK2
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    CarlosK2 Senior Member

    Screenshot_2024-07-23-13-19-04-63.jpg

    1901 (Left)
    1902 (Right)

    the great milestones were

    A) the Drag angle

    B) control of the gang of rustlers (Yaw, Roll and Pitch)

    C) understand Longitudinal balance

    Screenshot_2024-07-23-13-34-44-29.jpg

    Around the time of the Bleriot XI, stable longitudinal balance was gradually understood, and that was when aviation took off.
     
    Last edited: Jul 23, 2024
  12. CarlosK2
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    CarlosK2 Senior Member



    After a hundred years arguing like good Byzantines about the sex of angels... it seems that a clear consensus is being forged (ca. 2025): the low pressure, the suction, is ultimately due to viscosity: an object (an old wing, the stern of an old ship) moves, creates a hole, and falls into the hole.

    Screenshot_2024-07-23-16-58-02-13.jpg

    ---

    (Now i find out thanks to the Internet and a Greek historian that it is a western caricature of a serious discussion in Constantinople)
     
    Last edited: Jul 23, 2024
  13. CarlosK2
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    CarlosK2 Senior Member

    Screenshot_2024-07-23-17-50-50-69.jpg

    It seems to me to be a mistake (pedagogical and conceptual) to link the word Lift to the Lift based on 60% Low pressure.

    Motorboats fly with all the Lift created by 100% High pressure.

    To me it seems more logical and clear: we divert a fluid, by diverting that fluid a Force is produced.
     
  14. CarlosK2
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    CarlosK2 Senior Member

    IMG20240723183331.jpg

    Suppose our rig produces 1000 Newtons of Lift with 200 Newtons of Drag

    the Drag Angle is 11 degrees

    Suppose the daggerboard and rudder produce 1000 Newtons, and the hydrodynamic drag of the hull and its appendages is 300 Newtons + 100 Newtons of Hull Wind Drag = 400.

    The Hull Drag Angle is 22 degrees

    The upwind Beating Angle (between the apparent wind and the heading of the sailboat) is 33 degrees.

    (I mean that calculating is interesting and in some cases perhaps important; metaphysics, whether Byzantine or not, is of dubious usefulness)
     

  15. CarlosK2
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    CarlosK2 Senior Member

    Screenshot_2024-07-23-18-55-37-20.jpg

    Here the aerodynamic drag of the hull is added to the drag of the sails.

    Thousands and thousands of hours have been dedicated to this question and there are several tons published.

    It is more difficult to find good ideas to calculate High and Low Vertical and Lateral pressures in the hull of a monohull so as not to capsize when descending a big Wave.

    ---

    I already know that my idea is completely crazy: that sailboats are used to enjoy and not to suffer when the wind rises and the waves grow.

    ---

    Let's be honest: on most cruising sailboats, when the wind blows 20 knots, they think it's a storm. And the users are not to blame.
     
    Last edited: Jul 23, 2024
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