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A Anamolous Aerodynamic behaviour of small spheres?

  1. Jan 12, 2018 #1
    This refers to the behaviour of cricket balls. Every cricketer in the world believes that a cricket ball "swings" more when the atmospheric conditions are cool and damp (as in the UK) as opposed to hot and dry (as in Australia). I have watched a bit of baseball and I have never heard commentatators mention atmospheric conditions affecting the flight of the ball. Once the ball has left the hand there are only two forces acting - gravity and air resistance. "Swing" refers to the ball moving horizontally to the propelled direction (as well as vertically downwards of course).
     
  2. jcsd
  3. Jan 12, 2018 #2

    FactChecker

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    Cool air is denser and would have more noticeable aerodynamic effects. On the other hand, humid air is less dense, so that should decrease the aerodynamic effects. So I don't know why cool, humid air would be that different. (see figure in https://www.engineeringtoolbox.com/density-air-d_680.html )

    CORRECTION: I see in the figure in the link, that humidity has little effect in the temperature range of a sports event. So the primary effect would be the increased density of cold air. That should increase any aerodynamic effects in cold temperatures.
     
    Last edited: Jan 13, 2018
  4. Jan 12, 2018 #3

    anorlunda

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    There is such intense interests in sports, I expect that questions like that must have been studied using high speed cameras or other instruments. Good luck finding the studies. You may have more luck at sports forums than here.
     
  5. Jan 13, 2018 #4

    tech99

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    Does the baseball have a seam like a cricket ball? The seam is positioned at an angle to the path of the ball and makes the boundary layer unequal on the two sides, creating a sideways force.
     
  6. Jan 13, 2018 #5

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    Yes, the baseball has a seam and the pitcher often throws a ball that will maneuver different ways in flight: "curve ball", "knuckle ball", "slider", etc. But I don't remember hearing them comment on the effect of temperature or humidity on that aspect. They may have.
     
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