by Staff Writers
Washington DC (SPX) Jan 07, 2013
A new study published in the American Institute of Physics' (AIP) journal Physics of Fluids reveals that the normal rebounding of a ball changes when it is partially filled with a liquid.
Unlike an empty sphere or a solid rubber ball, which both rebound in a classical and well-understood fashion, a fluid-filled ball has its second bounce remarkably cut short.
A team of researchers from Brigham Young University in Provo, Utah, uncovered this phenomenon when they investigated what would happen if a sphere were partially filled with a liquid and how that would affect the way it bounces.
To their surprise, they discovered that on the first bounce the sphere behaved rather predictably, but on the second bounce it produced more of a thud than a bounce.
The reason for the stalled second bounce is that a large portion of the energy of the ball-liquid system is transferred from a falling mass into a liquid jet, dampening the rebound force.
This form of passive dampening was produced when two separate masses (sphere and liquid) that once behaved as one were suddenly separated, or decoupled.
As revealed in high-speed images, this decoupling didn't occur until the second bounce because the surface of the liquid first had to be perturbed by the initial bounce.
The researchers hope to apply these insights to engineer better methods of mitigating violent motions, ranging from improved sport helmet designs to removing some of the force associated with waves slamming into boats.
Further research will also help answer additional questions about the scale of the phenomenon, as well as how other types of fluids (such as non-Newtonian fluids) might react under the same circumstances.
Article: "Rebound and jet formation of a fluid-filled sphere" is published in Physics of Fluids; Authors: Taylor W. Killian (1), Robert A. Klaus (2), and Tadd Truscott (2). (1) Department of Mathematics, Brigham Young University (2) Department of Mechanical Engineering, Brigham Young University.
American Institute of Physics
Space Technology News - Applications and Research
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|