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Post by mikegarrison on Aug 31, 2011 22:26:22 GMT -5
Objects moving through air produce drag. Air doesn't want to slide along solid surfaces very well, but air readily slides over pockets of air moving in other directions. This is the key to the knuckleball. Um ... not really.
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Post by khitt on Aug 31, 2011 22:26:28 GMT -5
I know its baseball, but it has to be related somehow
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Post by khitt on Aug 31, 2011 22:27:26 GMT -5
Really, Mr Garrison? Uhmm not really? Interesting.....
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Post by mikegarrison on Aug 31, 2011 22:33:20 GMT -5
At least, that's my hypothesis for fitting the data (the data being the observation that the new balls jink around a lot more than the old balls used to). I'm jumping in late on this and haven't read the other thread. The data I've seen shows that the new volleyballs float less than the previous version. This video shows a part of the experimentation that went on in Molten's development of their new ball: I also suspect that the deformation of the ball on impact has quite a bit to do with the amount of movement created. Don't they use a Mikasa? Anyway, yes, if the ball is deformed that is going to have a big effect. I don't know how close to spherical the ball returns to.
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Post by Garand on Aug 31, 2011 22:45:28 GMT -5
Really, Mr Garrison? Uhmm not really? Interesting..... Mike Garrison clearly has substantial training in this area. I recognize this because I have a fair bit too, and he has a better working knowledge than me. Which is why I asked his opinion of my opinion. For instance, if you know how to calculate a Reynolds number and understand how it fits into the relationship between laminar and turbulent flow, then you're on the right track to start understanding these matters. If indeed you are fluent in these things, then I apologize. On the other hand, if you have not spent years in studying this material at the university level then it may be that your grasp of the subject is not what it needs to be in order to question MG's analysis. Where's Phaedrus when we need him?
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Post by mikegarrison on Aug 31, 2011 23:05:57 GMT -5
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Post by ESTRELLA on Sept 1, 2011 9:53:48 GMT -5
Get an aerospace engineer to tell you. If they can get those big pieces of metals and composites to stay in the air...for sure they can tell us why a ball floats.
Estrella
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Post by mikegarrison on Sept 1, 2011 10:13:51 GMT -5
Get an aerospace engineer to tell you. If they can get those big pieces of metals and composites to stay in the air...for sure they can tell us why a ball floats. Hey, that's a good suggestion. I should have thought of that.
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Post by Murina on Sept 1, 2011 10:30:39 GMT -5
Don't they use a Mikasa? Anyway, yes, if the ball is deformed that is going to have a big effect. I don't know how close to spherical the ball returns to. The Mikasa is the international ball. The Molten ball was designed in response to the Mikasa. They were developed along the same general principles. The literature for the Mikasa says the same thing as the Molten, so I'm pretty certain Mikasa came up with similar results for their ball.
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Post by mikegarrison on Sept 1, 2011 10:47:59 GMT -5
Don't they use a Mikasa? Anyway, yes, if the ball is deformed that is going to have a big effect. I don't know how close to spherical the ball returns to. The Mikasa is the international ball. The Molten ball was designed in response to the Mikasa. They were developed along the same general principles. The literature for the Mikasa says the same thing as the Molten, so I'm pretty certain Mikasa came up with similar results for their ball. Maybe what I wrote wasn't clear, so I'll elaborate. If a volleyball were a featureless sphere, then I would think this surface roughness would help it fly more truly. And it's possible that with no spin these balls do fly more truly. (One video on you tube doesn't necessarily prove that, though.) However, reports from the players seem to be that the new volleyballs (in particular, the Mikasa version) actually float around more dramatically than before. Assuming these reports are true, then I wondered why. The hypothesis I came up with is that the texturing does make the ball fly more truly -- when there is no seam influencing the flow separation. But that would have the side effect of actually making the seams more significant. When you have a small amount of rotation, seams move in and out of the region where the separation is critical. So maybe the new texturing actually enhances the float, but only when there is a small amount of rotation. When there is no rotation at all, maybe the ball would actually fly more truly. (And if the ball is not really spherical, that deformity will also affect the flight. But I'm assuming the deformation of the new ball is the same as the deformation of the old ball. Maybe that's not true? I don't know.)
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Post by Murina on Sept 1, 2011 12:27:58 GMT -5
Yeah, I get you.
I just wanted to point out that these balls are designed to reduce the float, and at least in one case it seems they were successful. I wonder if the empirical data would be corroborated in a lab environment? Maybe they didn't do as good a job as they had hoped to in the design?
IIRC the new ball is supposed to be played with less air pressure than the old ball. I suspect that would allow for greater deformation of the ball by the server.
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Post by Garand on Sept 1, 2011 18:00:13 GMT -5
I guess I'm a little lost as to why these balls were developed. Why reduce the amount of float when that particular characteristic plays such an important part in the serve and serve/receive game?
When the ball is served as a jump topspin or attacked in any other way, its rapid rotation and velocity should make all the issues of surface roughness or panels pretty much moot. I doubt that a dug or passed ball is going to be affected either way. To me, this means that the only benefit of this ball is to take away much of what makes a float serve effective.
Baseballs could be made with lower profile seams, but that would change the way pitches and batted balls move, probably to the detriment of the game. Volleyballs could be optimized for perfect flight, but that might also negatively affect the way the game is played. What am I missing here?
As a quick side note regarding deformation of the ball: after being struck, wouldn't the ball resume shape very quickly relative to it's flight time and wouldn't this make any deformation effect on the flight path very small?
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Post by mikegarrison on Sept 1, 2011 18:20:11 GMT -5
As a quick side note regarding deformation of the ball: after being struck, wouldn't the ball resume shape very quickly relative to it's flight time and wouldn't this make any deformation effect on the flight path very small? That was my assumption.
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Post by Deleted on Sept 1, 2011 20:11:40 GMT -5
I guess I'm a little lost as to why these balls were developed. Why reduce the amount of float when that particular characteristic plays such an important part in the serve and serve/receive game?When the ball is served as a jump topspin or attacked in any other way, its rapid rotation and velocity should make all the issues of surface roughness or panels pretty much moot. I doubt that a dug or passed ball is going to be affected either way. To me, this means that the only benefit of this ball is to take away much of what makes a float serve effective. Baseballs could be made with lower profile seams, but that would change the way pitches and batted balls move, probably to the detriment of the game. Volleyballs could be optimized for perfect flight, but that might also negatively affect the way the game is played. What am I missing here? As a quick side note regarding deformation of the ball: after being struck, wouldn't the ball resume shape very quickly relative to it's flight time and wouldn't this make any deformation effect on the flight path very small? That's the question I want answered. Do these balls mean the game will be moving more towards jump serves? (spin)
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MyNameHere
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Post by MyNameHere on Sept 4, 2011 0:06:53 GMT -5
I guess I'm a little lost as to why these balls were developed. Why reduce the amount of float when that particular characteristic plays such an important part in the serve and serve/receive game? When the ball is served as a jump topspin or attacked in any other way, its rapid rotation and velocity should make all the issues of surface roughness or panels pretty much moot. I doubt that a dug or passed ball is going to be affected either way. To me, this means that the only benefit of this ball is to take away much of what makes a float serve effective. Baseballs could be made with lower profile seams, but that would change the way pitches and batted balls move, probably to the detriment of the game. Volleyballs could be optimized for perfect flight, but that might also negatively affect the way the game is played. What am I missing here? As a quick side note regarding deformation of the ball: after being struck, wouldn't the ball resume shape very quickly relative to it's flight time and wouldn't this make any deformation effect on the flight path very small? This was in the original press release from FIVB: And manufacturer's description: So from the sound of all this, it fits FIVB's mantra well: "Keep the ball flying". Make the path of the ball more predictable (when tossing for serve, during the flight of serves and attacks), make the ball easier to control (with a softer feel, and with more surface area due to reduced number of seams), and reduce "sudden drop" (presumably to combat the effectiveness of the topspin serve, particularly in the men's game, but possibly also referring to float serves). It sounds as if some of the changes didn't have the intended effect re: float serves, but I think that was probably of lesser concern than making the jump serve and pass predictable. FIVB has been concerned for a while that volleyball is becoming increasingly boring to watch (from the standpoint of length of rallies). The server had too many advantages, so we introduced a passing specialist. The serve was effective when tough to track, so we added dimples to (theoretically) stabilize the flight. Referees were encouraged to be less harsh in judging ball handling faults. There has been talk of adding a "penalty" of sorts for missing serves (or consecutive serves or X number of serves in a set) to reduce the risk-reward approach of bombing jump serves. It does seem to be confusing now that the ball is not necessarily observed to be behaving as intended.
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