Reverse swing-what is it?

Though many of the cricket lovers have been hearing the term ‘Reverse Swing’, it is quite possible they might not have understood the exact meaning of it.

Normal swing occurs mostly when the ball is fairly new. As it wears more, the aerodynamics of the asymmetry change and it is more difficult to extract a large amount of swing.

When the ball becomes very old—around 40 or more overs, it can begin to swing towards the polished side rather than the rough side. This is known as reverse swing.

In essence, both sides have turbulent flow, but here the seam causes the airflow to separate earlier on one side. The result is always a swing to the side with the later separation, so the swing is away from the seam. See External Links

Reverse swing is difficult to achieve consistently, as it relies on uneven wear of the ball, tends to occur mostly in hot, dry weather conditions, and requires bowling at high speed.

Normal swing can be achieved at relatively moderate bowling speeds, but only the fastest bowlers can regularly produce reverse swing.

Reverse swing tends to be stronger than normal swing, and to occur late in the ball's trajectory.

Acknowledgement: wikipedia