The effect of atmospheric conditions on the swing of a cricket ball

The aerodynamic mechanisms that produce swing, and reverse swing in cricket are well understood and the phenomenon has often been measured in wind tunnel tests. However, it is widely believed throughout the cricketing community that atmospheric conditions can have a dramatic effect on a bowler's ability to make the ball swing, and this has perplexed the minds of sports engineers for decades. A sophisticated trajectory model was developed to investigate how different atmospheric conditions affect the swing of a cricket ball, and similar to previous studies, humidity was found to have no effect. Previous studies have suggested that certain atmospheric conditions may actually change the geometry of the cricket ball thereby exaggerating the asymmetric air flow around its body and thus increase the swing force. This hypothesis was tested by conditioning cricket balls inside an atmospheric chamber and then accurately measuring their geometry with a 3D laser scanner. The mass of the balls were also measured through the range of atmospheric conditions. It was found that the mass of a ball can change in different playing conditions, but no atmospheric conditions could cause a significant change to the ball geometry. It was concluded that if there is a real effect of atmospheric conditions on cricket ball swing it must be caused by an entirely different mechanism. It is proposed that new avenues for investigation should focus on how differing levels of cloud cover may affect localized air turbulence.