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-   -   Reverse Swing (https://www.pprune.org/tech-log/271247-reverse-swing.html)

Jambo Buana 8th Apr 2007 19:42

Reverse Swing
 
Anyone care to give me a laymans definition and working theory on this cricketing phenomenon and is there any future for it in aviation? I am only half joking.:cool:

TURIN 8th Apr 2007 20:46

Dunno about a future, but the Rooskies used the same technique to alter the trajectory of their (spherical) satellites during re-entry.

Jambo Buana 8th Apr 2007 21:33

From what I can gather, as the ball deteriorates the rougher side of the ball, at speeds in excess of 80 mph actually travels faster through the air and swings against the known direction which is normally away from the shiny side! Howzat then you aerodynamics gurus? Did the Ruskies beat up their capsule or something?
Does this have ANYTHING to do with the shark skin rudder that Airbus patented a decade or so ago?

HotelTango 10th Apr 2007 13:34

My dodgy understanding of reverse swing was that the fielding team work the shiny side of the ball by putting as much moisture on the shiny side as they can. At a certian point (about 40 overs) the shiny(moist) side of the ball has extra weight in it than the rough side. The rough side of the ball will travel through the air faster as it is lighter and the ball will reverse swing.
Reverse swing also works better when it is overcast. Not so good in Australia :}

lefthanddownabit 17th Apr 2007 02:59

A lot of mis-information about this. Journalists and commentators don't really understand it so often make things up (not that they'd normally do such a thing of course :) ). Most cricketers also don't really understand swing bowling, which is why there are so many old wives tales about it.

Overcast supposedly helps normal swing. Reverse swing is supposedly helped by hot and dry conditions. Actually it's all determined by the ball speed. Humidity or lack of it probably has little actual effect. It might affect the speeds at which swing happen perhaps.

Here is a link to an article which explains it all (except any humidity effect) very well.

http://content-uk.cricinfo.com/ci/co...ry/258645.html

Basically it's to do with the fact that airflow remains attached longer if the boundary layer is turbulent. If the separation is asymmetric the ball will swing. Turbulence is created by the seam and/or the rougher side of the ball. Normally the side towards which the seam is angled has later separation, so the swing is in that direction. With reverse swing the seam actually causes flow separation and the swing is then in the opposite direction.

aztruck 18th Apr 2007 08:59

Scottish aviation twin pioneer also has reverse swing. Still trying to find out why, probably something to do with the middle fin swinging the back end in the "wrong" direction after engine failure. Once its settles down everything happens between 75 and 80 knots. About right for a good seam bowler.
We should have chucked a few of them at the Aussies.....mind you 'm not sure it would clear the boundary on one....

WALSue 21st Apr 2007 21:37

that cricket lark is all greek to me.....and i understand the offside rule :)

TheGorrilla 22nd Apr 2007 01:46

.............. Please explain. :E

AirRabbit 22nd Apr 2007 18:55

Well ... I'd also ask for an explanation ... but never mind. I have enough trouble with Hockey!


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