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CATEGORIES:Isaac Newton Institute Seminar Series
SUMMARY:Bacterial Turbulence: A comparison with its fluid-
turbulence counterpart - Anupam Gupta (Indian Inst
itute of Technology)
DTSTART;TZID=Europe/London:20220616T140000
DTEND;TZID=Europe/London:20220616T153000
UID:TALK175619AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/175619
DESCRIPTION:Dense bacterial suspensions\, which are examples o
f active systems\, show spatiotemporal evolution t
hat is reminiscent of flows in turbulent fluids. H
ydrodynamical models have been developed to descri
be turbulence in dense\, quasi-two-dimensional (2D
) bacterial suspensions. This bacterial turbulence
happens at a low Reynolds number as opposed to fl
uid turbulence that happens at a high Reynolds num
ber. In this talk first I will discuss the Toner-T
u-Swift-Hohenberg (TTSH) model to describe the dyn
amics of dense bacterial suspensions\, which we de
rive from the Navier-Stokes equation. In the latte
r part\, I will discuss the recent results which w
e have got by solving numerically this TTSH model
equation. We carry out extensive direct numerical
simulations of Lagrangian tracer particles that ar
e advected by the velocity field in this model. We
demonstrate how the statistical properties of the
se particles help us \;to uncover an important
\, qualitative way in which irreversibility in bac
terial turbulence is different from its fluid-turb
ulence counterpart: For large but negative (or lar
ge and positive) values of the activity (or fricti
on) parameter\, the probability distribution funct
ions of energy increments\, along tracer trajector
ies\, or the power are positively skewed\; so irre
versibility in bacterial turbulence can lead\, on
average\, to particles gaining energy faster than
they lose it\, which is the exact opposite of what
is observed for tracers in 2D fluid turbulence.
LOCATION:Seminar Room 2\, Newton Institute
CONTACT:
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