• Alexandre

Master's internship on the Statistical Physics of granular clogs

Clogging phenomena, whereby a granular flow gets blocked at an opening (for instance, at the bottom of a silo), are an industrial issue as well as a common experience in everyday life. Microscopically, clogs are due to the formation of a stable arch or vault of grains across the opening. Diverse strategies have been proposed to destroy clogs, e.g., by applying vibrations [1], while some counterintuitive effects have been observed, such as the positive impact of an obstacle above the opening.

In the last decade, research has shown that the very concrete issue of clogging could be both efficiently and gracefully studied within the frame of statistical physics. The tentative idea of an out-of-equilibrium phase transition between a flowing phase and a clogged one has thus emerged [2], whose frontier depends on various paramters. Besides, models derived from the statistical physics of glasses (such as trap models) have recently succeeding in capturing several experimental observations [3], but their study is still nascent.

The internship will be mainly theoretical/numerical and will be aimed at deepening the exploration of these models and their relevance for clogging. Fundamental Statistical Physics issues will be tackled (e.g., the Kramers problem with solid friction). Interactions with the experimental Granular Lab in Pamplona (Spain), a leader in the field, are also foreseen.

The ideal candidate has a strong background in Statistical Physics and skills in numerical programming; (s)he will be based at iLM, in Villeurbanne (near Lyon).

References :

[1] LOZANO, Celia, ZURIGUEL, I., et GARCIMARTÍN, A. Stability of clogging arches in a silo submitted to vertical vibrations. Physical Review E, 2015, vol. 91, no 6, p. 062203.

[2] ZURIGUEL, Iker, PARISI, Daniel Ricardo, HIDALGO, Raúl Cruz, et al. Clogging transition of many-particle systems flowing through bottlenecks. Scientific reports, 2014, vol. 4, p. 7324.

[3] NICOLAS, Alexandre, GARCIMARTÍN, Ángel, et ZURIGUEL, Iker. Trap model for clogging and unclogging in granular hopper flows. Physical review letters, 2018, vol. 120, no 19, p. 198002