Role of gravity in motion of granular materials: Discovery could have applications in pharmaceutical industry, space missions

In a paper called "Granular Convection in Microgravity," which is due to be published Dec. 24 in Physical Review Letters, Dr Naomi Murdoch and Dr Ben Rozitis, at The Open University's Faculty of Science describe how they and five other researchers made this research on the basis of a European Space Agency Fly your Thesis competition in 2009.

The researchers used the unique gravitational environment available on-board the Zero-G aircraft, to perform experiments to investigate the role of gravity in a granular flow. Little was known about the role of gravity in granular materials and they found that unlike normal gravity, which produces two components of grain motion, the secondary flow is suppressed in zero gravity.

"This allowed us to explore the behaviour of granular material in conditions that become very close to the ones encountered on the surface of much smaller bodies than the Earth, " said Dr Murdoch and Dr Rozitis. "Such an understanding of the role of gravity is important to interpret the images of granular surfaces sent by space missions visiting other solid bodies of our solar system and will be of use to pharmaceutical companies looking for more efficient ways to sort the properties of drug powder."