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funny airflow effect from fan

Discussion in 'PC Hardware' started by Hugh Jarss, 2009/03/17.

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  1. 2009/04/02
    Christer

    Christer Geek Member Staff

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    This is the misconception:
    The rest is based on the laws of physics:
    Your comments:
    Yes but I was making a short remark, not a full coverage.
    That's the rationale behind the perpetuation of the "simplified explanation ". People don't care as long as they get to their vacation spot.
    The top, yes but not the convertible ... :p ... !
    ... and at high altitudes. Compare the U2 with its large wing and high aspect ratio (wing-area²/span)!
    Not to create drag, that's an unwanted pay-off. Some flaps extend the area (fowler flaps) but others don't. The key is to deflect more air downwards.

    (In a flapped glider, you can set negative (upwards deflecting) and positive (downwards deflecting) flap settings. The negative settings are for high speed flight at low angles of attack as opposed to positive settings which are for high angles of attack while flying slow and circling. The extreme negative setting is the landning setting at which the drag actually is wanted for steep approaches.)

    Christer

    Edited:

    "The extreme negative setting is the landning setting at which the drag actually is wanted for steep approaches. "

    should read

    "The extreme positive setting is the landning setting at which the drag actually is wanted for steep approaches. "
     
    Christer,
    #21
  2. 2009/04/02
    Bill

    Bill SuperGeek WindowsBBS Team Member

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    lol I care that the simplified explanation is still correct. I know that every surface of a wing affects flight and the manipulation of that surface does to. I know at high altitudes, to stay aloft at slow speeds, you need lots of surface area for lift, as with the U2. If short on surface area, you better be fast (SR-71). I also know fan blades are wings - when talking physics. A properly designed fan blade is designed with and for a specific application/environment - open blade, housing, duct, etc. Changing the environment changes the characteristics of the air flow past that wing. That's what I was trying to point out with the fan and paper - in a valiant but feeble attempt to bring this back on topic.

    Gliders, I would think, use extreme examples of manipulation of the various surfaces and edges - having only the ever changing currents to work with, you would need to take every advantage of any opportunity. I don't recall any metal alloy skinned airplanes riding thermals - though I suppose the U2 came close.

    Otherwise, I assume that ground comes up at you pretty darn quick. ;)
     
    Bill,
    #22


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  4. 2009/04/02
    Christer

    Christer Geek Member Staff

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    Let's agree to disagree ... ;) ... and to get on with computers, fans and ribbons!

    Your second quote drew my attention to an error I made. I have edited my previous post.

    Christer
     
    Christer,
    #23
  5. 2009/04/02
    Bill

    Bill SuperGeek WindowsBBS Team Member

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    Hmmm, I thought we were in agreement - that is - Hugh's fan experiment is not realistic - and it has to do with the aerodynamics of the fan and turbulence (manipulation of the airflow).
     
    Bill,
    #24
  6. 2009/04/02
    Christer

    Christer Geek Member Staff

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    Yes, in that case we are in agreement! (I thought that case was "closed" and we had derailed the topic further into a discussion about how wings generate lift.)

    Christer
     
    Christer,
    #25
  7. 2009/04/02
    Bill

    Bill SuperGeek WindowsBBS Team Member

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    I suspect my lay-understanding took us round about. Sorry about that.
     
    Bill,
    #26
  8. 2009/04/03
    Christer

    Christer Geek Member Staff

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    No problem ... :cool: ... you seem to be bright ... ;) ... for a quinquagenarian! (Me too ... :p ... quinquagenarian that is but maybe not so ... :eek: ... bright.)

    Christer
     
    Christer,
    #27
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