Fluid mechanics of table tennis balls—discovery of 'spin-crisis'

June 27, 2017, University of Electro-Communications
Three rotor launching machine "Chiquita." Credit: University of Electro-Communications

Research conducted by Takeshi Miyazaki and colleagues at the Complex Fluids Lab at UEC, Tokyo, covers environmental fluid mechanics in massive systems such as flight of projectiles and motion of vortices in the Earth's atmosphere and oceans, as well as so-called granular flows where studies focus on determining how the behavior of individual particles affect macroscopic fluid flow.

Intriguingly, the other major area of research addresses mechanics in sport including aerodynamics of flying arrows and spinning balls used in baseball, and recently table tennis balls.

"It is surprising that the aerodynamic properties of table tennis balls are not clear," says Miyazaki. "This may be because engineers have little interest in spinning spheres with Reynolds numbers less than 105, as is the case for the lightweight table tennis balls. But such is research is important for sports science."

In fluidics the Reynolds number is a guide to the transition from stable, laminar to rougher and turbulent motion of objects. Miyazaki and colleagues used high speed video cameras to track and monitor the trajectories of table tennis balls launched by a specially designed 'three rotator machine'.

"We unexpectedly found a dip in the lift coefficient for table tennis balls traveling at a spin rate of less than 0.5," explains Miyazaki. "We refer to these results as 'spin-crisis' because they imply that more spin does not mean more lift. In fact, too much spin on the causes it to go down."

This research highlights the many unresolved phenomena in .

Lift coefficient as a function of the spin parameter SP. Credit: University of Electro-Communications

Explore further: Knuckleball machine delivers soccer science

More information: T Miyazaki et al. Lift crisis of a spinning table tennis ball, European Journal of Physics (2016). DOI: 10.1088/1361-6404/aa51ea

Related Stories

Knuckleball machine delivers soccer science

July 12, 2016

Wind tunnel and high-speed camera data help researchers to explore the zigzag secrets of one of football's most unpredictable shots and provide clues to much older scientific mysteries

Invention breathes new life into tennis balls

June 14, 2005

The traditional cry of "new balls please" at tennis courts throughout the country could become a thing of the past thanks to a new invention by a University of Bath student. Aimée Cubitt, a final year Mechanical Engineering ...

Physicists revisit spin-bowling puzzle

July 21, 2016

Latest calculations reveal why small variations in the rotation of the ball applied by slow bowlers in cricket can cause batsmen big problems even before deliveries have pitched on the ground

Explained: How does a soccer ball swerve?

June 16, 2014

It happens every four years: The World Cup begins and some of the world's most skilled players carefully line up free kicks, take aim—and shoot way over the goal. The players are all trying to bend the ball into a top corner ...

Two-ball bounce problem explained

July 14, 2015

Researchers from the University of Bristol have revisited a well-known classroom demonstration where a lighter ball is dropped on top of a larger heavier ball and offer a model to explain the phenomenon.

Recommended for you

How bacterial communities transport nutrients

December 12, 2018

Under threat of being scrubbed away with disinfectant, individual bacteria can improve their odds of survival by joining together to form colonies, called biofilms. What Arnold Mathijssen, postdoctoral fellow in bioengineering ...

New method gives microscope a boost in resolution

December 12, 2018

Scientists at the University of Würzburg have been able to boost current super-resolution microscopy by a novel tweak. They coated the glass cover slip as part of the sample carrier with tailor-made biocompatible nanosheets ...

Copper compound as promising quantum computing unit

December 12, 2018

Quantum computers could vastly increase the capabilities of IT systems, bringing major changes worldwide. However, there is still a long way to go before such a device can actually be constructed, because it has not yet ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.