The drag coefficient of tennis balls

The aim of this study is to gain an understanding of the motion of a tennis ball during flight. A wind tunnel was used to measure the aerodynamic forces on a tennis ball, and hence calculate their drag coefficients at wind speeds up to 136mph. The drag coefficient was relatively constant with increasing velocity for each brand of ball tested, and a larger ball had a similar drag coefficient to a standard sized ball. It was found that raising or lowering the nap increased or decreased the drag coefficient by almost 6%. In conclusion, a larger drag force on a tennis ball can be achieved through an increase in diameter or raising the nap of the ball.