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Discussion in 'Spin Bowling' started by Richard the Third, Feb 19, 2011.
hahaha which is to say, Woolmer's experts are wrong!
grip it and rip it folks, grip it and rip it.
The more research I do, the more complex this all seems, look at this http://plus.maths.org/content/os/latestnews/may-aug06/teamgeist/index and this is just a football which as it says is relatively smooth, we're working with a ball that has a dirty great seam on it and two little grooves if its a 4 panel ball. Add to that rough and smooth sides and you're talking about a very complex set of aerodynamics. Woolmers piece along with Pencils piece all have disclaimers/caveats, both of which confirm that much of what they're saying is pure speculation. Woolmer... "If we are correct in our speculations, and figure 5.23 correctly illustrates the physics of what occurred that afternoon". I think both Woolmer and Pencil start out with intro's that both also suggest that there has been very little done in the way of concrete research looking at all aspects of the things that some of us are able to do with the ball.
I might stop posting here and start a new thread till I get my head around this more or give up and just accept that it happens (Drift) without knowing why it happens, what causes it, and what happens to increase or decrease it etc. As Spin Lizard says "Grip and rip it" knowing full well that it might happen. It's that "Might" aspect that bugs me, even Stuart Macgill answered one of my emails a couple of years ago, along with Menno Gazendum, both of them alluded to the fact that they couldn't "Turn on" drift to order, it was either happening or it wasn't. They could bowl alternate drift, non drift at will.
Absolutely. I've just used those exact words to someone about this very topic. You don't want consistency in anything but line and length. Some drift more than others and some dip more than others. That is all a part of a spinner's effectiveness. Ultimately, just spin it as hard as you can and try to stick to the basics of grip and release as you do it.
Yeah I've just read this as well. It looks like a totally lost cause to me having read this again, and as I said earlier this is to do with a far simpler sphere...
Chaotic behaviour like this is not revealed by models such as the one described above (in (2)) which rely on the aerodynamic parameters not changing as the ball progresses smoothly along an orderly trajectory. More incisive analysis is required to understand such behaviour and researchers resort to sophisticated computer packages involving computational fluid dynamics (CFD) to crack these problems. Using such techniques the flow of air around the ball can be simulated in great detail and the aerodynamic forces caused by conventional spin, or discrete disturbances triggered by the panel or seam patterns, can be accurately predicted.
Such work may lead to the definition of an aerodynamic standard for soccer balls, stipulating the tolerances for the amount of swerve produced by a given speed and spin rate. The controlling authority for world football, FIFA, issues specifications for every conceivable property of the ball such as weight, sphericity, recoil in a bounce and water absorbency, but as yet there are no such specifications for the aerodynamic properties. The ball can swerve or bob about unpredictably in flight as much as the aerodynamic forces allow.
Football supporters probably feel that players like David Beckham do their talking with their feet but mathematicians may demur; there is one great challenge left. All of the methods I have described, from Tait's rudimentary approach, to the complexity of computational fluid dynamics, derive ultimately from one of the great unresolved problems of mathematical physics, the Navier-Stokes equations. Since the mid-19th century these have defied exact solution and are one of the seven Millennium Problems identified by the Clay Mathematical Institute. Solve the Navier-Stokes equations and you can claim a prize of $1 million (find out more in How maths can make you rich and famous II). It is sobering to think that whilst this outcome would set the world of mathematics on fire, the prize would not pay the wages of a middling professional footballer for longer than half the playing season!
That article makes a very pertinent point in all of this and this is about the changing nature of aerodynamic parameteres. To put it more simply: there is never consistency in the airflow around a cricket ball. Some atmospheric conditions (such as humidity levels) will create slightly different levels of resistance on the ball as it travels through the air. This is something much more specific to what we see with swing rather than with the magnus effect, but it will apply to a spinning ball too. Add to that the varying physical nature of the cricket ball (new, old, scuffed up, shiny on one side and, perhaps most importantly if the seam is not completely upright, a slightly out of shape cricket ball) and you have various aerodynamic parameteres changing from delivery to delivery - nevermind from one day to the next.
I always remember bowling a ball in the nets about a year or so ago that drifted a huge amount, probably as much as that Warne/Gatting delivery. It wasn't bowled with anywhere near the amount of pace or revs as the Warne delivery and yet it moved a ridiculous amount. I've never drifted a ball that much before or since. It wasn't windy (plus, my club's nets are fairly well shelted from the wind - which is not ideal really) and I have no idea why it moved so much. But, I am sure the condition of the ball, the position of the seam and the atmospheric conditions were the factors in that movement and not the revs. It showed to me that revs will move the ball via the magnus effect, but other factors will move the ball in a manner we would usually just call "swing". This is what I mentioned a few pages back. Spin will cause the ball to behave unusually and other factors, such as seam position and conditions, will too. I suspect that the Warne/Gatting ball was more than just the Magnus effect, simply because we never really saw Warne move a ball so much on a regular basis. The fact that the ball happened to land on a perfect line and length to then take the top of off, made it the memorable delivery it is. However, the norm for Warne was, probably, about 30%-40% less drift than that. I just mentioned that because, in my opinion, we shouldn't look at that ball as an example of the magnus effect solely.
A cricket ball does exactly the same thing as a ricket ball except with less revs because it has air in it, if a left footed footballer kicks the ball flying saucer type, just like a leg break flying saucer the ball will drift to the right....
bending soccer ball is cooking my noodle slightly, I'll admit. I think perhaps different aerodynamics, also different spin being applied. <shrug>
I do know that if I kick an aussie rules ball in a spiral (torpedo), it does as predicted by magnus effect.
I was thinking about this last night and was thinking about seam position. If you think about it, the seam position for a legspinner is a perfect seam position for standard away swing bowling. Therefore, if you are bowling with a relatively new ball or a ball that is equally worn on both sides, then bowling with a clean and upright seam when bowling a leggie will tend to create away-swing. This will happen as the spin is creating in-drift. Essentially, swing and drift working against each other. The forces of the magnus effect will possibly be stronger so that you may well get a little drift but a lot of drift could be inhibited by seam position. With a ball in this condition it is probably best to scramble the seam to remove any away swinging forces.
However, if the ball is in a state that could produce reverse swing (scuffed up on one side and smooth/shiny on the other side), then the seam position that normally produces away-swing will produce in-swing as long as the shiny side of the ball is on the right-hand side. If you are bowling a leggie with a ball in this condition, then a clean and upright seam (with the shiny side on the right hand side) may well produce in-swing. Thus, you will have swing working with and not against in-drift, producing a lot of movement into the batter. I wouldn't be surprised if this was what was happening with the Warne-Gatting wicket.
I suspect a spun ball doesn't swing, but it is interesting to think about.
Warne-Gatting: Ideal conditions (breeze/humidity/whatever) plus Gatting not knowing Warne's abilities, plus young Warne with good shoulder absolutely ripping it, all conspired to make it 'the ball of the century he's a magician'. I'd guess Warne bowled plenty of deliveries that followed that exact path, that a more wary batsman blocked or padded away. Just a hunch.
It's difficult to really know or test whether a spun ball swings because if you are bowling with a new-ish ball any swing would simply restrict in-drift (or away drift if we talk about an off-spinner with a seam angled into a batter like an in-swinger). But, I'm sure it's something that could be looked at. I'd love to know either way.
I'll be up at the nets tomorrow (if the snow clears!). I'll prepare a couple of balls for reverse swing and try a few things out.
I don't see why a spun ball shouldn't swing. Swing bowlers will impart a fair amount of backspin after all.
I haven't got a copy of his book to hand, but Brian Wilkins did an analysis comparing swing at a range of seam angles and velocities. If I recall correctly, there are some unusual effects at the higher seam angles where the swing reverses strongly. So, maybe this could come into play with the leg break with a little overspin.
I have to (somewhat) correct myself again. Just been browsing this paper
Cricket Ball Aerodynamics - myth vs. science
I guess NASA should know. Especially if the author is also a mate of Imran Khan! He claims that a spin rate of 11.4 rev/s or thereabouts is optimal for swing, and that further increases in spin will lessen the amount of swing as the spin is then effectively roughening the shiny side of the ball.
Looking at the results, it seems that swing bowlers should pay a lot of attention to how much they are spinning the ball! It's quite a difference.
Warne talked about leg spin bowling at the lunch break a couple of days ago, but he didn't really say anything of note. He did say that he will be launching his new website in the next month.
Not a whole lot of interesting stuff.
Just seen this....
To dodge this fate the legspinner should toil alone in a wire net, or out in the backyard, away from judging eyes. He should do this for at least one decade but ideally two or more. Only then should he enter top-flight cricket. It is a barren and thankless existence.
From here http://www.espncricinfo.com/magazine/content/story/372200.html
He should do it for 10 years, ideally 20 years or more.
I wouldn't say that long. But then, if you're talking about professional cricket and you're talking about being very good at professional legspin bowling, then it may well be a long old time. It is an all or nothing type of bowling. Bill O'Rielly told Richie Benaud it is something like a period of 4 years hard work. It's not really possible to put a time limit on it because it depends on the individual, how much natural ability he has and also what sort of work he is doing. If you are alone in the nets and working away, you don't really know for sure if you are repeating the correct action over and over again. I tend to video my bowling as much as I can and then watch it back. But I'm only watching it back when I've finished and got home. Lately, I've been tending to open the hand a bit too early (as if bowling a topspinner or a googly). I wouldn't have known that if I hadn't been recording my bowling and watching it back.
Went out to practice today, it was very cold. Bowled pure shit........ I havent played much cricket since 2 months and school has ruined my cricket too... When i was coming back from the ground my friend my brother and i couldnt stop laughing because we realised how shit we are.....
+ive grown about 10 cm since 6 months. So my length is getting messed up, now that im 15 i really need to do something about my bowling
Yeah so thats how my school has ruines my life its my timetable from Monday to Saturday (left to right) and from 8 am to 6 pm , i have classes when theres a box and i dont have class when theres nothing + im in a british section so i have 9 jours of english per week which doesnt help now when can i play CRICKET ?
Yeah the growth thing is an issue that affects blokes your age, it's to do with your physical size growing, but a little bone in your ears balancing canal not growing at the same rate. It eventually catches up though. Just hang in there, this is the time when a lot of Wrist Spinners lose faith!
Jesus that's a lot of time in school! You're at school on Saturday?
We've been outside as well and done a bit of easy bowling, just to keep loose and keep our hand in. Not that bad so far, but yeah bloody cold! I think you've got it worse in France though. Hopefully in some nets in next couple of days a bit warmer as well.