Active Matter

Crowd of microswimmers

Our ambition in this interdisciplinary project is to couple two a priori very distinct domains which are crowd movements and active suspensions of microswimmers. The modeling of crowd movements has become a very active research field, and deep debates still animate the community on how to model certain behaviors such as panic movements for example. It has also been established that some paradoxical effects observed in crowd dynamics persist in a wide variety of systems (herds, granular, colloid, etc.). A common physical mechanism behind these universal statistical behaviors remains to be discovered. Here, we wish to analyze the behavior of a new class of systems: that of active suspensions that intrinsically involve hydrodynamic interactions between micro-swimmers. How do hydrodynamics affect the crowd dynamics of micro-swimmers? This interdisciplinary project involves physicists and applied mathematicians.

Salima RAFAI, Philippe PEYLA
Collaborations : Bertrand MAURY, Sylvain Faure (LMO Orsay)
Edouardo AL ALAM (Doctorant 2019 - )

Collective swimming of fishes

Fish move based on their perception of and response to their social and physical environment (grouping, alignment, coordination, self-organization in schools, predation, etc.). Their movements generate strong hydrodynamic disturbances in the surrounding fluid on length scales much larger than the typical size of an individual fish. Fish use the thrust generated by the acceleration of the surrounding fluid to swim. In this study, we aim to understand the coupling between fish cognitive behaviors (alignments, preferred directions, ...) in the presence of hydrodynamic interactions between individuals within a school and in a complex environment.



Philippe PEYLA, Catherine QUILLIET, Aurélie DUPONT
Collaborations : Christian GRAFF, Laboratory of Psychology and Neuro-Cognition, University Grenoble Alpes ; Thibaut METIVET, Laboratoire Jean Kuntzmann, INRIA.
Renaud LARRIEU (Doctorant 2020 - )