Current and former Postdocs featured on the cover of Journal of Fluid Mechanics
Dr Sylvain Viroulet (Postdoc 2013-2016), Dr James Baker (PhD Student 2012-2016) and Dr Andrew Edwards (current postdoc) have had their work on granular flow over obstacles highlighted on the front cover of the Journal of Fluid Mechanics.
Sylvain, James and Andrew showed how it is possible to generate two different steady-state granular flows over a smooth bump. In one configuration the grains flow rapidly over the bump and take off to form a jet, while in the other there is a shock upstream of the bump, which dramatically increases the thickness of the oncoming flow and slows it down, so that it does not take off. It is possible to switch between the two flows by momentarily blocking the jet, or manually scraping some grains away from the shock, as shown on the animation below. Understanding how granular materials flow over obstacles is very important for designing natural hazard defences for snow avalanches as well as flow control in industry.
The paper is available open-access at https://doi.org/10.1017/jfm.2017.41
Sylvain is now working in the Seismology Group at the Institut de Physique du Globe de Paris (IPGP).
James successfully defended his PhD in September 2016 and is now working as a Postdoc at the University of Sydney.