Golf ball impacts, greens and the golfer

This paper gives a brief overview of the results of a 3 year project to study the relationship between the characteristics of golf greens and the impact of golf shots on them. To this end, an apparatus was developed to project spinning golf balls direclty onto golf greens with the resulting impacts recorded on film. The apparatus was usied on eighteen golf courses resulting in 721 useful photographs of impacts. Two types of green emerged from analysis of the photographs; on the first, the ball tended to rebound with topspin, while on the second, the ball retained backspin if the initital backspin was large enough. Eleven tests were used to determine the characteristics of greens and the relationships between the characteristics were results linked to the impact study. It was found that it was easier to retain backspin on the rebounding ball on a green that was freely drained and had a low amount of Poa annua in its sward.

A mathematical model was developed to simulate the impact of the ball with the turf. The model showed good agreement with experiment for vertical impacts with no spin and gave sensible results for oblique impacts with backspin.