Aerodynamic characteristics and flow field analysis by PIV on peculiar flight behavior of soft tennis balls

Abstract

Soft tennis may have a peculiar flight unlike other ball games. The flight is not a flight with a parabola, but a flight in which the ball takes up a rising trajectory without falling. It is because of the negative Magnus effect. However, negative Magnus force has been studied for many years, but the specific conditions for its occurrence are not known. Therefore, the purpose of this research is to observe the range of this negative Magnus effect and to investigate the force occurring in a peculiar flight aerodynamically and the state of the flow. PIV measurement was conducted to analyze the flow around the ball when negative magnus effect occurred. As a result, it was found that the Magnus force and the negative Magnus force are related to the flow behind the ball. In addition, it was confirmed that the speed of the vertical speed of the ball was switched. As a result, the position of the separation point changed and it was found that a negative Magnus force was generated.