Anamolous Aerodynamic behaviour of small spheres?

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    Fluid dynamics Spheres
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Discussion Overview

The discussion centers on the aerodynamic behavior of small spheres, specifically comparing the flight characteristics of cricket balls and baseballs under varying atmospheric conditions. Participants explore the effects of temperature and humidity on ball swing and maneuverability, as well as the physical properties of the balls themselves.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that cricket balls "swing" more in cool and damp conditions compared to hot and dry conditions, while noting that baseball commentators do not typically mention atmospheric effects on ball flight.
  • One participant suggests that cool air is denser, which could enhance aerodynamic effects, but questions the role of humidity, noting that humid air is less dense and may reduce these effects.
  • A correction is made regarding the impact of humidity on air density, indicating that cold air's density is the primary factor influencing aerodynamic effects.
  • Another participant expresses curiosity about existing studies on this topic, suggesting that high-speed cameras or instruments may have been used to investigate these effects.
  • Participants discuss the seam of the baseball, questioning whether it affects the ball's flight in a manner similar to the cricket ball, and mention various pitching techniques that manipulate ball movement.
  • There is a reiteration that while baseballs have seams that can create different flight paths, the influence of temperature and humidity on these effects is not commonly discussed in commentary.

Areas of Agreement / Disagreement

Participants express differing views on the effects of atmospheric conditions on the flight of cricket and baseballs, with no consensus reached on the significance of humidity versus temperature. The discussion remains unresolved regarding the extent of these effects and the availability of empirical studies.

Contextual Notes

Participants note the complexity of the factors influencing ball flight, including air density, seam effects, and the potential lack of empirical studies directly addressing these questions.

John_RB
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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).
 
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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.
 
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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.
 
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.
 
tech99 said:
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.
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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