Programme

P.5 -- Poster, VCTP-45

Date: Tuesday, 13 October 2020

Time: 08:30 - 10:00

Chaoticity and mixing in a dilute suspension of rods

Lance Christopher VI M. Plan (1), Stefano Musacchio (2), Dario Vincenzi (2), and Massimo Cencini (3)

(1) Institute of Theoretical and Applied Research, Duy Tan University, Hanoi 100000, Viet Nam (2) Université Côte d’Azur, CNRS, LJAD, Nice, France (3) INFN, Sezione di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy

It has been previously shown (Groisman and Steinberg, Nature, 2000) that the a dilute amount of extensible polymers at low Reynolds number create the so-called elastic turbulence, a chaotic regime that has characteristics reminiscent of hydrodynamic turbulence, albeit smoother. Here we show that the rotational dynamics of microscopic rods in a viscous fluid at low Reynolds number causes a significant increase of the flow resistance and can likewise generate a turbulent-like behaviour. Numerical simulations of the dynamics of the solution reveal that this phenomenon is associated to a transition from laminar to chaotic flow. Polymer stresses give rise to flow instabilities which, in turn, perturb the alignment of the rods. This coupled dynamics results in the activation of a wide range of scales. The temporal decay of the variance of the scalar field and its gradients shows that this chaotic flow strongly enhances mixing.

Presenter: Emmanuel Lance Christopher VI M. Plan