Brain teaser: wind power conundrum

Discussion in 'Free Thoughts' started by Arthur Smith, Jan 11, 2022.

  1. Arthur Smith Registered Member

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    New here, so I may have missed if this has come up before.

    Is it possible to conceive of, design and construct a vehicle that, powered only by the wind, can sustain speed in excess of that wind while travelling in the direction of that wind?
     
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  3. Beer w/Straw Transcendental Ignorance! Valued Senior Member

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    Are you asking if a windmill can move faster than the wind pushing it?
     
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  5. Arthur Smith Registered Member

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    Not if you mean a building used for grinding grain.
     
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  7. Arthur Smith Registered Member

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    Examples of vehicles powered only by the wind are yachts, sailboats, land-yachts, ice-yachts, hot air balloons etc.
     
  8. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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    Possible there is a YouTube video

    Years ago MythBusters did something with a yacht driving it with a fan inside the yacht

    Might help if the video exist

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  9. Arthur Smith Registered Member

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    But do you think the scenario is possible?
     
  10. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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    Not my area to even speculate even
    But if a yacht can tack INTO the wind who knows?

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  11. Arthur Smith Registered Member

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    Well, one thing no yacht can do is sail directly downwind any faster than the wind.
     
  12. Michael 345 New year. PRESENT is 72 years oldl Valued Senior Member

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    Ummmm try

    https://www-sciencefocus-com.cdn.am...ts-sail-faster-than-the-wind-propelling-them/

    Yes, although it sounds implausible.

    With the wind blowing from behind and sails perpendicular to the wind, a boat accelerates. The wind speed on the sail is the difference between the vessel’s forward speed and that of the wind. Once the boat reaches the same speed as the wind it’s impossible to go any faster. But with the wind blowing from the front, the boat turns its sails into the wind by about 45°. The sails divert the wind slightly as it blows across them, which slows the wind and exerts a sideways force on the sail. The keel (the large fin that extends down beneath the hull) cancels out the sideways force. But, if the sail is angled correctly, some of that force also drives the boat forward. The vessel continues to accelerate until that force is matched by the drag of the water. So, with clever streamlined hull designs a boat can sail faster than the wind

    As I said not my arena. But Mr Google ask nicely "can you sail faster than the wind" Bibiitty-Bop-Boo comes out with the above

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  13. Arthur Smith Registered Member

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    Yes. Ice-yachts are even faster than hydroplane yachts, apparently capable of approaching 8-10 times wind speed. But not directly downwind.
     
  14. DaveC426913 Valued Senior Member

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  15. Arthur Smith Registered Member

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  16. Arthur Smith Registered Member

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  17. RainbowSingularity Valued Senior Member

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    are you prejudice against grinders ?

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    your question is open ended

    you have not defined your medium

    land wheels caterpillar tracks water
    muddy bog
    alligator infested sewage pond
    the moon
    the moon on a low moon wind day
    etc...

    i know the new Americas cup boats can exceed wind speed
    but that technology & medium is not wheels & moving around buildings might be hard
    more soo if you need to parallel park beside a very expensive vehicle with no car insurance

    being picky just for the sport of it
    convection ? thermal ? when is wind not thermal or convection ?
    etc...

    is a hot air balloon powered by wind or thermals ?

    pushed by wind
    but lifted/powered by thermal exchange variance
    no thermal exchange variance then its just a bouncy castle in a shit storm
     
    Last edited: Jan 11, 2022
  18. Arthur Smith Registered Member

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    @ Rainbow. Wind, in this instance can be construed as air in movement with respect to another medium.
     
  19. RainbowSingularity Valued Senior Member

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    steam ?

    steam has added heat energy

    im being picky for conversation purposes

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    i guess there comes a point where friction becomes a compulsory element
     
  20. sideshowbob Sorry, wrong number. Valued Senior Member

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    The misconception is that sailboats are propelled by air pushing against the sail. In fact, sailboats are propelled by air moving over the surface of the sail. So the movement of the sailboat is not directly related to the speed of the wind.
     
  21. RainbowSingularity Valued Senior Member

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    negative force vector conveyance

    discrepancy actuator
     
  22. Arthur Smith Registered Member

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    There has to be a transfer of kinetic energy. Air molecules are slowed by loss of momentum which is gained by the sail.
     
  23. billvon Valued Senior Member

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    Absolutely. Sailboats do that all the time. They "cheat" by generating lift between the water and air, both of which are moving at different velocities. In fact, boats can go INTO the wind at a speed faster than the wind.
     

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