High-Speed Video Image Analysis of Air Flow around a Table Tennis Ball

We tried to visualize the air flow around a flying table tennis ball and analyze the flow velocity field and vortex shedding using PIV. The images of the air flow were visualized by oil mist and a laser light sheet with a metal halide light and recoded by a CMOS type of high speed video camera at a rate of 1,000 to 10,000 fps. Our objective is to discuss from the viewpoint of fluid mechanics if a knuckle ball trajectory flickers with a zigzag motion of inward and outward curves, or not. The final goal of this study is to present scientific information about knuckle ball trajectory to table tennis players and coaches who are struggling to develop new tactics and skills.