Swing bowling not due to humidity, research suggests

[1983-2011]

The phenomenon of swing bowling, in which a cricket ball veers sideways during flight, is not influenced by humidity, researchers say. Cricketers and sport scientists alike have long hypothesised that high humidity may increase the swing effect. But precise 3-D studies of cricket balls under varying humidity showed no effect on the balls' shapes. A report due in instead suggests that cloud cover increases swing by stilling the air. Much like the path of a "curve ball" in baseball or a looping corner kick in football, the swing effect comes from setting up different kinds of air flow on opposite sides of the ball - smooth or "laminar" flow on one side and chaotic "turbulent" flow on the other. But why the effect is more noticeable during some matches, and even some days in the same match, has had researchers and players stumped. "Lots of scientists have always tried to discuss this idea around cricket ball swing and the effect of atmospheric conditions, and people talk about humid days being really important," said study co-author David James of Sheffield Hallam University's Centre for Sport Engineering Research. "The leading hypothesis as to why cricket balls swing was around the fact that the seam on the cricket ball will swell on a humid day, becoming more pronounced, and that might lead to more swing," he told BBC News. Dr James and his colleagues John Hart at Sheffield and Danielle MacDonald at AUT University in New Zealand made use of the centre's "climate chamber", in which atmopheric conditions can be tightly controlled. They used a 3-D laser scanner to monitor differently conditioned balls reacted under varying humidity, but found humidity had no detectable effect on the ball's geometry. Instead, they have pitched in another idea: that bright sunshine - or the lack of it - is to blame for variation in swing. "When the ground heats, it makes convection currents which make the air rise off the cricket pitch - that creates turbulence in the air on a sunny day," Dr James explained. "On a cloudy day you get stiller air, because you don't get these convection currents coming off the ground." Stiller air does less to affect the imbalance of smooth and chaotic flow on either side of the ball that leads to swing, so cloud cover could indirectly be the culprit. Dr James concedes that the team's hypothesis must now be put to a test under controlled conditions, but they are convinced that humidity is not the variable that should put batters on the back foot. "We fairly rigorously went through every possible thing around humidity and debunked it," he said.

http://www.sciencedirect.com/science/article/pii/S1877705812016463 http://www.bbc.co.uk/news/science-environment-18262145

[The Outsider]

But players also suggest that they don't get much swing when it's very cold, so I am not convinced by the ground heat reducing swing argument either.

[Cricketics]

The biggest impact of swing what I have noticed as a bowler is when you literally releaser the ball with some wrist movement. Don't confuse it with holding the ball in certain way and release and moving the fingers/wrist when releasing. Even the most gloomy/cloudy conditions doesn't leave any impact as much as the velocity of the ball when released from hand does.

[rkt.india]

The biggest impact of swing what I have noticed as a bowler is when you literally releaser the ball with some wrist movement. Don't confuse it with holding the ball in certain way and release and moving the fingers/wrist when releasing. Even the most gloomy/cloudy conditions doesn't leave any impact as much as the velocity of the ball when released from hand does.

:agree:

[rkt.india]

There are two different things swing in the air and seam of the pitch. Some times people are confused in these two things. There are very few bowlers in the world who can swing the ball in the air and release of the ball and wrist position play a big role in that.

[ravishingravi]

The biggest impact of swing what I have noticed as a bowler is when you literally releaser the ball with some wrist movement. Don't confuse it with holding the ball in certain way and release and moving the fingers/wrist when releasing. Even the most gloomy/cloudy conditions doesn't leave any impact as much as the velocity of the ball when released from hand does.

Agreed. But gloomy conditions does help. It happens time and time again. The sun is out suddenly it is flat again.

[bangladeshifan]

Agreed. But gloomy conditions does help. It happens time and time again. The sun is out suddenly it is flat again.

yes specially in england.

[CSK Fan]

The biggest impact of swing what I have noticed as a bowler is when you literally releaser the ball with some wrist movement. Don't confuse it with holding the ball in certain way and release and moving the fingers/wrist when releasing. Even the most gloomy/cloudy conditions doesn't leave any impact as much as the velocity of the ball when released from hand does.

Thats seam movement, not swing. Thats what Asif was an expert of. Seam happens off the pitch with wrist position. Swing happens in the air and a good seam position helps like with Anderson

[rkt.india]

Thats seam movement' date=' not swing. Thats what Asif was an expert of. Seam happens off the pitch with wrist position. Swing happens in the air and a good seam position helps like with Anderson[/quote'] How you release the ball also determines the swing? The bowlers who release the ball swings it more like Steyn, PK.