A query: What exactly is a "Reverse Swing"?
Karanraj
what is exactly the definition of reverse swing in the cricket books? Also if
anyone knows how to go about reversing swinging?
A very curious opening batsman :)
Karanraj
Pig is trying to become Tiger means how it will become Tiger? Pig will
become cat, then it will get chance for dog, then it will get chance
for cheetah and lion and then if it is showing own type of stiff it is
becoming Tiger." Private-anna"
Achilles
shiny, so if a bowler wants to bowl an inswinger the shiny side of the ball
is towards the right. Swing can be explained using Bernoullis principle and
its basically the same idea used in designing aircraft wings to give the
plane lift.
Reverse swing is the art of swinging the ball in a direction opposite to
this i.e the ball swings in the direction of the rough side of the ball.
Usually batsman could guess which way the ball was going to swing by
noticing the way the bowler held the ball just before he delivered it, and
that is the reason why reverse swing became such a success when it was first
bowled by the Pakistanis as it really confused the batsman!!
It can usually be accomplished with an aging ball, where I guess the shiny
side itself isnt that shiny anymore. Thought I dont have a clue about how a
bowler can accomplish it!! It will interesting if someone in the group can
shed some light on it.
"Karanraj" <kara...@aol.com> wrote in message
news:20010320092934...@ng-fk1.aol.com...
Arawak
<20010320092934...@ng-fk1.aol.com>:
>Can the learned ones, specially bowlers, elaborate on this one? What is
>it and what is exactly the definition of reverse swing in the cricket
>books? Also if anyone knows how to go about reversing swinging?
>
>A very curious opening batsman :)
According to the all-knowing Colin Croft, there is no such thing as reverse
swing... it's either an outswinger or an inswinger and that's that.
Now while I am the first to admit that Coft is an idiot, I thik there's
something in what he says. Perhaps the issue of how the bowler holds the
ball is what makes a difference but many of us don't pay the least bit of
attention to how the bowler holds the ball or watch the way his hand goes
as the ball comes out.
Late swing is the real trouble, IMHO. Doesn't matter to me which way the
ball swings if it does it early on but if it happens 3/4 of the way down
the pitch you're probably already committed to a position that is now
several inches away from where you should be.
Arawak
Prasad Shetty
and
> what is exactly the definition of reverse swing in the cricket books? Also
if
> anyone knows how to go about reversing swinging?
taken from rediff.com (prem panicker)
Reverse Swing: This particular delivery, delivered from a shade wide of the
crease, holding a line on off stump, drifting a shade out and then at the
very last instant swinging in viciously, is already something of a legend
thanks to the Younis-Akram combine.
And at its heart is a basic aerodynamic principle. What the Pakistan
quicks - and the likes of Darren Gough, who have been quick to catch on to
the secret - have been doing is basically simple. Keep one side of the ball
scuffed, as the swing bowler used to do. But rather than shine the other
side of the ball, use spit and sweat to make the opposite side slick, wet
and relatively heavier than the scuffed side. By which point, aerodynamics
takes over, the heavier side begins to 'fall away', that is, perceptibly
slow down as opposed to the lighter side. With the result that at the very
late stage, the ball moves dramatically in towards the batsman, swinging
away from its natural line and taking the batsman by surprise. Delivered at
a full length, the late swing defeats both the defensive jab and the drive,
both strokes dictated by the off stump line, and crashes more often than not
into the middle and leg stumps.
pks
Rocky Raccoon
is it and
> what is exactly the definition of reverse swing in the cricket
books? Also if
> anyone knows how to go about reversing swinging?
>
> A very curious opening batsman :)
Currently, any swing which a bowler gets after 20 odd overs is called
reverse
swing by commentators.
I sorta agree with Arawak about Colin Croft's view.
James Foster
>
> kara...@aol.com (Karanraj) wrote in
> <20010320092934...@ng-fk1.aol.com>:
>
> >Can the learned ones, specially bowlers, elaborate on this one? What is
> >it and what is exactly the definition of reverse swing in the cricket
> >books? Also if anyone knows how to go about reversing swinging?
> >
> >A very curious opening batsman :)
>
> According to the all-knowing Colin Croft, there is no such thing as reverse
> swing... it's either an outswinger or an inswinger and that's that.
>
Well I hesitate to come right out and call him an idiot because of
course
in a sense he is correct - if it swings in to the right-hander it is an
inswinger; if it swings away it is an outswinger. The point about
reverse swing is that the ball is held and delivered in the same way
as for an outswinger and instead it swings in.
James
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tel: (808) 956 2360 JAMES FOSTER HIGP
fax: (808) 956 3188 1680 East West Rd
EMail: jfo...@XTRACTsoest.MEhawaii.edu Honolulu
URL: http://www.soest.hawaii.edu/~jfoster HI 96822
James Foster
>
> "Karanraj" <kara...@aol.com> wrote in message
> news:20010320092934...@ng-fk1.aol.com...
> > Can the learned ones, specially bowlers, elaborate on this one? What is it
> and
> > what is exactly the definition of reverse swing in the cricket books? Also
> if
> > anyone knows how to go about reversing swinging?
>
> taken from rediff.com (prem panicker)
> And at its heart is a basic aerodynamic principle. What the Pakistan
> quicks - and the likes of Darren Gough, who have been quick to catch on to
> the secret - have been doing is basically simple. Keep one side of the ball
> scuffed, as the swing bowler used to do.
True to this point: it *is* a basic aerodynamic principle, and it is
aided
by have a rough and smooth sides of the ball, however this:
> But rather than shine the other
> side of the ball, use spit and sweat to make the opposite side slick, wet
> and relatively heavier than the scuffed side. By which point, aerodynamics
> takes over, the heavier side begins to 'fall away', that is, perceptibly
> slow down as opposed to the lighter side.
is nost palbably wrong. It is a very popular misconception (esp. in Aus)
but I am amazed so few people remember their basic school physics and
the
famous apocryphal Galileo & the Tower of Pisa tourist bombing
experiment.
Light & heavy sides have nothing to do with aerodynamics in the first
place - the air flow can't tell whether it is a heavy or light side, and
Making one side heavier doesn't make it "fall away" as Galileo pointed
out.
The key aerodynamic principle for reverse swing is the change from
a laminar (sheet-like) flow regime around both sides of the ball to
tripping turbulent flow on one side. The turbulent flow is able to
hug the side of the ball longer: this means that there is less of a
pressure drop on that side creating a sideways force that pushes the
ball towards the lower pressure (laminar-flow/smooth) side.
To trip the transition from laminar to turbulent flow you need to bowl
faster (or create a rougher surface on one side). Until you reach that
transition point the effect of the rough and smooth sides is completely
opposite - the rough side looses the boundary layer sooner & so has a
bigger pressure drop than the smooth side and the ball moves towards
the rough side. The transition, when it occurs, is very abrupt - and it
takes a finite time to develop (from the back to the front of the ball)
which probably explains the initial normal swing motion before the
sudden
onset of reverse swing.
Wind-tunnel tests show that you can make a new ball reverse swing if you
bowl at ~90+ mph. Once there is a contrast in roughness between the
sides it is acheivable at lower speeds. The trick is to find the right
speed for the condition of the ball. (Or at least I imagine that is the
trick - having never been able to bowl remotely fast enough to get it
going myself!)
samarth harish shah
I think Croft has a point. This term "reverse swing" was never heard of
for the first 115 years of test cricket, I reckon! So, did reverse swing
not exist then? (As in, did bowlers not practice it?) Or was it called
something else? Basically, my question is where was this "reverse swing"
for the first century of test cricket?
-Samarth.
Arawak
>I think Croft has a point. This term "reverse swing" was never heard of
>for the first 115 years of test cricket, I reckon! So, did reverse swing
>not exist then? (As in, did bowlers not practice it?) Or was it called
>something else? Basically, my question is where was this "reverse swing"
>for the first century of test cricket?
Hanging out with the flipper?
Arawak
Yuk Tang
Arawak wrote in message <906AAC102sea...@127.0.0.1>...
I thought the flipper was invented some 50-odd years after Test cricket
started, courtesy of Clarrie Grimmett. At least according to Fingleton, who
called it the "flicker" after the noise the thumb makes on flicking the ball
out.
Whereas reverse swing was invented on the dustgrounds of Pakistan, where the
shine wears off very quickly indeed, and another method is needed to
differentiate the two sides of the ball.
Cheers, ymt.
Mike Holmans
, samarth harish shah <shs...@students.uiuc.edu> writes
>On Tue, 20 Mar 2001, Arawak wrote:
>
>> According to the all-knowing Colin Croft, there is no such thing as reverse
>> swing... it's either an outswinger or an inswinger and that's that.
>
>for the first 115 years of test cricket, I reckon! So, did reverse swing
>not exist then? (As in, did bowlers not practice it?) Or was it called
>something else? Basically, my question is where was this "reverse swing"
>for the first century of test cricket?
With the new ball, you keep one side shiny, and it swings one way. When
the ball is old, with one side fairly smooth and the other side very
rough, it swings both later and in the other direction, assuming you
bowl with the same action as you did before.
Obviously, the conditions existed for this type of swing to take place
with the old ball during the first century of Test cricket. But until
the 1970s, it was basically a surprise. Swing bowlers didn't realise
that a roughed-up ball would be useful to them, so they didn't encourage
roughing up, and they didn't try their usual outswinger deliveries,
because they didn't think it would work. When it happened, it was an
aberration, and both bowler and batsman tended to think it was a pretty
lucky wicket when he was bowled.
Then Sarfraz Nawaz started to deliberately rough up one side of the
ball, including using bottle-tops. And he showed some other Pakistani
bowlers what happened when he did it. And lo and behold, what had
occasionally happened but no-one really knew why became a regular
occurrence, and "reverse" swing could be produced at will.
Sarfraz was a bowler of limited ability, and needed a grossly roughed-up
ball in order to produce the effects. Obviously, the technique was
attractive to swing bowlers, and so others tried it. People like Imran
and Wasim Akram were a great deal more skilful than Sarfraz, and could
swing the ball more anyway. When they tried it with bottle-tops, they
found they got far too much swing. In the end, as they came to
understand how it all worked, they didn't need to tamper with the ball
at all, at least not beyond what the usual wear and tear and rubbing
saliva into one side of the ball will do.
The bottle-tops were, of course, illegal, and their use led to the more
stringent provisions about umpires inspecting balls at regular
intervals, but the ultimate effect of that cheating has been beneficial,
as it has added to the armoury which bowlers have at their disposal.
Without the cheating, the phenomenon would probably not have been
discovered and controlled - at least for a few more years, as it is
entirely possible that some loonies with a wind-tunnel and a research
grant might have discovered it independently.
Cheers,
Mike
--
1888 - last time England won a 3-match series after going one down
1979 - last time England completed four consecutive series wins
2001 - England win two successive series in Asia for the first time
DG
"James Foster" <jfo...@XTRACTsoest.MEhawaii.edu> wrote in message
[snipped]
>
> The key aerodynamic principle for reverse swing is the change from
> a laminar (sheet-like) flow regime around both sides of the ball to
> tripping turbulent flow on one side. The turbulent flow is able to
> hug the side of the ball longer: this means that there is less of a
> pressure drop on that side creating a sideways force that pushes the
> ball towards the lower pressure (laminar-flow/smooth) side.
>
> To trip the transition from laminar to turbulent flow you need to bowl
> faster (or create a rougher surface on one side). Until you reach that
> transition point the effect of the rough and smooth sides is completely
> opposite - the rough side looses the boundary layer sooner & so has a
> bigger pressure drop than the smooth side and the ball moves towards
> the rough side. The transition, when it occurs, is very abrupt - and it
> takes a finite time to develop (from the back to the front of the ball)
> which probably explains the initial normal swing motion before the
> sudden
> onset of reverse swing.
This is the most accurate description of reverse swing that I have seen. It
is consistent with basic fluid mechanics. To put "regular swing" into
perspective, what is happening there is that the seam is tripping turbulent
boundary layer on the side of the ball that the seam is directed.
Essentially both reverse and regular swing are utilising the same fluid
mechanic principles, from what I understand. The difference is that in one
instance the seam is acting to trip coundary layer flow, while in reverse
swing it is the disparity in roughness.
Please correct me if I'm wrong!
DG
samarth harish shah
<snip>
> Whereas reverse swing was invented on the dustgrounds of Pakistan, where the
> shine wears off very quickly indeed, and another method is needed to
> differentiate the two sides of the ball.
Hmm. So, you're implying its a recent "discovery", eh? That nobody knew
before (say) the 70s or so when it was born in Pakistan? I wonder what
some old-timers would say about it. Say Fred Trueman, for example.
(Expecting Mike to insert something humorous here.) Or Richie Benaud. What
would they reply if you told them your theory that reverse swing wasn't
discovered in their day - that it didn't exist then? What if you used this
as a criterion in comparing fast bowlers of today with those of
yesteryear. For example, if I said, "Wasim is better than Davidson because
Wasim could reverse-swing it, not Davidson", how valid would statement be?
Also, when did this propagate to other countries? After the 1992-3
England vs Pakistan series? When, for example, would McGrath or Darren
Gough have learnt it? As a grade or Shield cricketer in NSW some time in
the early to mid 90s, in the case of McGrath?
-Samarth.
paul
<achilles8...@hotmail.com> wrote:
>Usually a cricket ball will swing towards the side of the ball which is
>shiny, so if a bowler wants to bowl an inswinger the shiny side of the ball
>is towards the right. Swing can be explained using Bernoullis principle and
>its basically the same idea used in designing aircraft wings to give the
>plane lift.
>Reverse swing is the art of swinging the ball in a direction opposite to
>this i.e the ball swings in the direction of the rough side of the ball.
>Usually batsman could guess which way the ball was going to swing by
>noticing the way the bowler held the ball just before he delivered it, and
>that is the reason why reverse swing became such a success when it was first
>bowled by the Pakistanis as it really confused the batsman!!
>It can usually be accomplished with an aging ball, where I guess the shiny
>side itself isnt that shiny anymore. Thought I dont have a clue about how a
>bowler can accomplish it!! It will interesting if someone in the group can
>shed some light on it.
>
>
The way it was described on the TV commentary yesterday, it just
depends which side the shiny side of the ball is on. The bowler tries
to hold the ball in such a way that the batsman cannot see the ball.
In the main, the Indians appeared to be picking the swing fairly well
yesterday.
paul x is the spam filter
uroburos
Arawak <sea...@arawak.on.ca> wrote in message
news:906A73F00sea...@127.0.0.1...
> Now while I am the first to admit that Coft is an idiot, I thik there's
> something in what he says. Perhaps the issue of how the bowler holds the
> ball is what makes a difference but many of us don't pay the least bit of
> attention to how the bowler holds the ball or watch the way his hand goes
> as the ball comes out.
And I thought I was the only one who read the ball off the pitch!
I've never looked at what happens to the ball coming out of the hand...I
have a policy of smother/play dead straight unless rank.
But then again, its probably different for a real batsman.
uroburos
Ian Galbraith
[snip]
:I think Croft has a point. This term "reverse swing" was never heard of
:for the first 115 years of test cricket, I reckon! So, did reverse swing
:not exist then? (As in, did bowlers not practice it?) Or was it called
:something else? Basically, my question is where was this "reverse swing"
:for the first century of test cricket?
Didn't Imran Khan invent it? Its just a different method of swinging the
ball, swinging it when its old not new.
--
Ian Galbraith
Email: igalb...@ozonline.com.au ICQ#: 7849631
"It's precisely when humour is offensive that we need it the most. Comedy
should provoke, blast through prejudices, challenge preconceptions.
Comedy should always leave you different than when it found you."
-Duckman
Craig Sutton
and
> what is exactly the definition of reverse swing in the cricket books? Also
if
> anyone knows how to go about reversing swinging?
>
> A very curious opening batsman :)
>
Reverse swing is all about roughing up one side of the ball once it get
older and keeping the other side polished up. Which will upset the air flow
when the ball is in the air. For a bowler to get good reverse swing the
whole team has to know how to properly condition the ball and which side is
the one to be polished or which side needs the odd fingernail mark on it
Craig Sutton
"samarth harish shah" <shs...@students.uiuc.edu> wrote in message
news:Pine.GSO.4.10.101032...@ux13.cso.uiuc.edu...
The balls may have changed a lot since then. In the 2nd test we saw one of
the Pakistani bowler keep running his fingers through his hair then rubbing
the ball. I think the umpire had a bit of a word to him about that as well.
Maybe he didn't wash his hair for a few days and was applying a little oil
from his hair onto the ball to help with polishing it.
Did anyone else notice? the commentators did.
Craig Sutton
"Yuk Tang" <yo...@dial.pipex.com> wrote in message
news:3ab7e953$0$12246$cc9e...@news.dial.pipex.com...
>
> Whereas reverse swing was invented on the dustgrounds of Pakistan, where
the
> shine wears off very quickly indeed, and another method is needed to
> differentiate the two sides of the ball.
>
> Cheers, ymt.
also known as reverse bottle top theory
ratskillet
"Nikhil Shah" <nik...@newsville.com> wrote in message news:3AB7E6C1...@newsville.com...Superb explanation James, The basic rule is when the ball is "new" and if you
have the shine to the right it is a inswinger and when the shine is to the left
when the seam is held upright it becomes an outswinger.Now one assumption made for the regular swing is when the ball is new
the shape is perfectly round and very hard.The reverse swing comes into affect with the old ball is for several reasons
1. The ball no with shiny side is not as shiny
2. The hardness of the ball contributes the laminar flow and
turbulence now becomes dynamic in nature
3. The Shape is no-longer round, hence the pressure drops
on that side creating a sideways force that pushes the
ball towards the lower pressure side.
The Australian team had this problem with OLD balls in T1/T2. I have
noticed that when the Aussies complained about the hardness
and shape and when a they got a different ball replaced with the same
"oldness" the ball starting reverse swinging really well because of the
shape and hardness. In India this effect where the ball looses its shape
and hardness with the Indian manufacturers is very common.Regards
Nikhil
Mad Hamish
wrote:
>
>Arawak wrote in message <906AAC102sea...@127.0.0.1>...
>>shs...@students.uiuc.edu (samarth harish shah) wrote in
>>
>>>I think Croft has a point. This term "reverse swing" was never heard of
>>>for the first 115 years of test cricket, I reckon! So, did reverse swing
>>>not exist then? (As in, did bowlers not practice it?) Or was it called
>>>something else? Basically, my question is where was this "reverse swing"
>>>for the first century of test cricket?
>>
>>Hanging out with the flipper?
>
>
>I thought the flipper was invented some 50-odd years after Test cricket
>started, courtesy of Clarrie Grimmett.
True according to every source that I've read.
Mad Hamish
<shs...@students.uiuc.edu> wrote:
>On Tue, 20 Mar 2001, Yuk Tang wrote:
>
><snip>
>
>> Whereas reverse swing was invented on the dustgrounds of Pakistan, where the
>> shine wears off very quickly indeed, and another method is needed to
>> differentiate the two sides of the ball.
>
>Hmm. So, you're implying its a recent "discovery", eh? That nobody knew
>before (say) the 70s or so when it was born in Pakistan?
I don't think that anyone did it consistantly. There was probably the
odd ball where it happened.
iirc Sarfraz is meant to have taught Imran Khan how to do it, I
haven't heard any talk about where Sarfraz learnt it..
> I wonder what
>some old-timers would say about it. Say Fred Trueman, for example.
>(Expecting Mike to insert something humorous here.)
Trueman would say that he did it but black and white footage always
made the ball look like it went straight..
> Or Richie Benaud. What
>would they reply if you told them your theory that reverse swing wasn't
>discovered in their day - that it didn't exist then?
Well Richie's never disagreed with the idea that the Pakistani bowlers
introduced it.
Trueman has written in a book that one reason why spinners have fallen
off in effect is that modern balls last better and also that the
fertiliser used now provides a much smoother surface so that the ball
doesn't get damaged as much.
According to the book in Austrlaia the ball typically stopped swinging
at around the 10 over mark in the 30s...(8 ball overs of course)
> What if you used this
>as a criterion in comparing fast bowlers of today with those of
>yesteryear. For example, if I said, "Wasim is better than Davidson because
>Wasim could reverse-swing it, not Davidson", how valid would statement be?
It's definately an argument you could use.
It's far from conclusive. Some of the best bowlers didn't even swing
the ball much...
Also the actual ability to deliver a ball with reverse swing appears
no different from normal swing. It's the technique of treating the
ball that is different.
>
>Also, when did this propagate to other countries?
Various times.
I'd say it was starting to in the early 90s.
>After the 1992-3
>England vs Pakistan series? When, for example, would McGrath or Darren
>Gough have learnt it? As a grade or Shield cricketer in NSW some time in
>the early to mid 90s, in the case of McGrath?
Dunno about Gough, I think McGrath developed it fairly recently, quite
a bit after his test debut.
MCC
Mad Hamish wrote:
[snip]
> >After the 1992-3
> >England vs Pakistan series? When, for example, would McGrath or Darren
> >Gough have learnt it? As a grade or Shield cricketer in NSW some time in
> >the early to mid 90s, in the case of McGrath?
>
> Dunno about Gough, I think McGrath developed it fairly recently, quite
> a bit after his test debut.
McGrath of course doesn't swing the ball that much, nor
really does Gillespie. That's why Fleming's poor form has
been telling on this current tour. McG and Gillespie are
excellent bowlers, but like Lillee rely on seam more than
swing. In Australia, seam bowling has been considered far
more effective than swing for a very long time (and as a
result not many A quicks are that good at swinging the ball)
Regards,
Michael Creevey
Arawak
>> holds the ball is what makes a difference but many of us don't pay the
>> least bit of attention to how the bowler holds the ball or watch the
>> way his hand goes as the ball comes out.
>
>And I thought I was the only one who read the ball off the pitch!
>
>I've never looked at what happens to the ball coming out of the hand...I
>have a policy of smother/play dead straight unless rank.
>
>But then again, its probably different for a real batsman.
The old boys who have coached me over the years have always gone on and on
about reading the action of the bowlers, especially spinners to know what
the ball is going to do.
I never have had any luck with it, so I gave up and just concentrated on
where the ball is going to pitch and either getting up to it or away from
it.
Imagine my surprise when a good friend brings back MCC Masterclass from
Engerlund and there in plain print is Viv Richards saying that he never
tried to read the ball coming out of the bowler's hand. His theory -- and
it makes great sense to me -- is that half the time the bowler doesn't
really know what the ball is going to do so why would the batsman? He
advocates getting to the pitch of the ball so the it really doesn't matter
which way it turns. By extension, I think going back on a short ball gives
you time to see what it does and play it accordingly.
Now that I no longer worry about the bowler's hand I have a lot more time
to pick up the flight, line and length of the ball and have had greater
success with the bat.
Arawak
Yuk Tang
Arawak wrote in message <906B5748Dsea...@127.0.0.1>...
>
>Now that I no longer worry about the bowler's hand I have a lot more time
>to pick up the flight, line and length of the ball and have had greater
>success with the bat.
I find that I leave the ball more elegantly if I can read which way the
wristie is going to turn. The problems start when the ball is aimed at the
stumps. Also, for Moby-types who are out there, short-arses like myself can
usually play seamers cross-batted with some safety to anything short of
half-volley length. For that reason, spinners are more threatening than
wannabe pacemen.
Cheers, ymt.
Jim Garner
>>>>I think Croft has a point. This term "reverse swing" was never heard of
>>>>for the first 115 years of test cricket, I reckon! So, did reverse swing
>>>>not exist then? (As in, did bowlers not practice it?) Or was it called
>>>>something else? Basically, my question is where was this "reverse swing"
>>>>for the first century of test cricket?
Well, seeing as I seem to be the only guy on this ng that can remember the
last 115 years from experience, let me add my bit . . .
In 195o, when I first played club cricket in Eng, the term was unknown (by
me anyway, and I doubt anybody else knew it). The convention was that
the new ball swung and the old one didn;t, but I do recall a commentator,
maybe John Arlott or Swanton, saying in some match that the ball was so
old that the only way to get swing was by a "body off break", whatever
that was. I think maybe it was causing the ball to rotate on a vertical
axis, which would have imparted the same kind of swing that you get with a
football. I tried it and it didn;t work for me.
If you think about it, you can get that kind of rotation by holding the
ball with the flat of the hand, but a bowler can only rotate it on one
direction.
Bowlers had always polished the ball, but I first heard of polishing it
on only one side sometime in the early fifties, though maybe that wasn't a
new idea at the time. Not knowing anything about fluid flow dynamics or
the golf ball effect, I thought the polished side of the ball would slip
through the air faster, In fact, the reverse is the case, and I wonder
whether the word "reverse" comes from this confusion.
I've read that Freddie Truman said he used reverse swing in his later
years. He passed 30 in 1962, so the technique and the phrase may well
have come into play in the sixties.
Some posters have associated late swing with reverse swing. I thought
late swing had been around forever, although truth to tell I sometimes
have suspected that late swing is merely an optical illusion, the result
of a canny bowler moving the ball just barely enough to beat the bat, so
the batsman doesn't realize it's swinging until too late.
An interesting side query: If rough surfaces offer less air resistance
than smooth, how come reconnaissance Spitfires in WW2 were polished for
an extra 20 knots of speed and how come aircraft skins, bullets and
racing cars are not dimpled?
--
Jim Garner, sage and dogsbody. an...@ncf.ca
(613) 526-4786; 759B Springland, Ottawa, ON K1V 6L9 Canada
"Eliza Doolittle's honeymoon: 'How nice of you to let me come.'"
Arawak
<snipped interesting post>
>An interesting side query: If rough surfaces offer less air
>resistance than smooth, how come reconnaissance Spitfires in WW2 were
>polished for an extra 20 knots of speed and how come aircraft skins,
>bullets and racing cars are not dimpled?
Well, sharks have very rough skins (from personal experience!) and golf
balls are dimpled. Unfortunately I slept through most of fluid mechanics so
I can't remember the hows or whys.
Arawak
Rakesh Srivastava
Couldn't resist - have to throw in my $0.02. Hey, I stayed awake in the
fluids class. :-)
Rough surface does not offer less resistance - always.
For any object there are 2 components to resistance -
1. Skin friction drag
2. Wave drag (Shape effect)
1. As the name suggests, this comes from the friction of the fluid with
the surface of the object. Laminar flow offers less skin friction than
turbulent flow. Rough surface will turn the flow turbulent right away.
However, given enough "travel distance" every laminar flow will eventually
become turbulent. This depends on the viscosity, density, velocity and
distance.
2. Wave drag is because of the shape of the object - a square object will offer
more resistance to air than say a round object or an airfoil shape. This
is a reulst of the flow behind the object - the more the flow is separated
the more resistance it will offer.
The combination of these two forces determine the total resistance or in
fluids lingo - drag force on the object.
Here come the compications -
A laminar flow offers less resistance but separates earlier than a turbulent
flow. Separation means the flow leaves the surface creating a pocket of
"dead" or very low speed flow.
A separated flow offers more resistance than an attached flow.
Now, since the aircraft shapes are designed to keep the flow attached pretty much
through out, a smooth surface will offer overall less resistance. Hence a smooth
skin.
No matter what you do, flow will separate behind any ball. Going over a ball,
since laminar flow will separate faster than turbulent flow, in order to
reduce the drag it pays to dimple the golf balls. This makes the flow turn
turbulent and hence remain attached longer offering less resistance resulting
in longer travel distance.
As far as a Shark is concerend, I guess the rough skin is there to keep the
flow attached longer otherwise the water may separate which given the right
condition could create cavitation - a major problem. Don't know if there are
other reasons as well.
Hope I have been able to clarify a few things.
As far as reverse swing is concerned, I always believed that the ball first
moves in one direction and then swings in the opposite direction, confusing
the batsmen. So, for example, the ball may move as an out-swinger in the
initial phase of the trajectory only to change direction and move as an
in-swinger. This is just what I thought and concluded watching the
tapes of the balls called by the comentators as reverse-swing. I may be
totally off the mark though.
Rakesh
--
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Rakesh Srivastava | phone: 216-433-6045
MS 49-8 | fax: 216-977-7051
NASA Glenn Research Center |
Cleveland, Ohio 44135 | email: Rakesh.S...@grc.nasa.gov
-----------------------------------------------------------------------------
Moby
> I find that I leave the ball more elegantly if I can read which way the
> wristie is going to turn. The problems start when the ball is aimed at the
> stumps. Also, for Moby-types who are out there, short-arses like myself can
> usually play seamers cross-batted with some safety to anything short of
> half-volley length. For that reason, spinners are more threatening than
> wannabe pacemen.
It's entirely up to you, but I think I'd prefer it if you just ducked..
you might hit the first three, but the fouth one's gonna hurt...
Moby.
He of the variable bounce.
Peter Watkins (au)
At least it was when I bowled (for 20 years). There are some great
explanations elsewhere in this thread.
Summary:
1. new ball. big seam. swing away from shiny side.
2. old ball. no seam. big difference in roughness. swing towards shiny
side. (reverse swing)
PS. No one has mentioned the fact that normal swing works best when the
ball is spinning backwards at about 8 revs per second. This is quite slow,
so to swing the new ball, you don't snap your wrist. You keep the fingers
behind the ball, and let the ball slide out, thus giving it a slow enough
backspin. As opposed to cutters, where you flick your wrist as hard as you
can. The increased spin bites into the wicket, and increases the effect of
the seam in cutting the ball off the wicket.
PPS. Someone in this thread confused swing and swerve. Swerve happens with
spinners, where the ball swerves in the opposite direction to the spin.
Baseball pitchers use swerve, because there is no seam.
--
--
Please remove XYZ to reply.
Nikhil Shah <nik...@newsville.com> wrote in message
news:3AB7E6C1...@newsville.com...
>
> Superb explanation James, The basic rule is when the ball is "new" and if
you
> have the shine to the right it is a inswinger and when the shine is to the
left
> when the seam is held upright it becomes an outswinger.
> Now one assumption made for the regular swing is when the ball is new
> the shape is perfectly round and very hard.
>
> The reverse swing comes into affect with the old ball is for several
reasons
>
> 1. The ball no with shiny side is not as shiny
> 2. The hardness of the ball contributes the laminar flow and
> turbulence now becomes dynamic in nature
> 3. The Shape is no-longer round, hence the pressure drops
> on that side creating a sideways force that pushes the
> ball towards the lower pressure side.
>
> The Australian team had this problem with OLD balls in T1/T2. I have
> noticed that when the Aussies complained about the hardness
> and shape and when a they got a different ball replaced with the same
> "oldness" the ball starting reverse swinging really well because of the
> shape and hardness. In India this effect where the ball looses its shape
> and hardness with the Indian manufacturers is very common.
>
> Regards
>
> Nikhil
>
>
>
MCC
Jim Garner wrote:
> An interesting side query: If rough surfaces offer less air resistance
> than smooth, how come reconnaissance Spitfires in WW2 were polished for
> an extra 20 knots of speed and how come aircraft skins, bullets and
> racing cars are not dimpled?
[snip]
Well, rough surfaces offer more air resistance, however the
point is the imbalance created by the rough/smooth creates
swing (in theory).
Regards,
Michael Creevey