NARC 5/31 - Cancelled

[Robert Baraldi]

Hi everyone, 

As the subject line suggests, there will be no NARC tomorrow (5/31) due to the plethora of numerical activity around the department this Thursday. Since next week is exams, there are no more NARC meetings for the spring quarter. 

Other things happening in AMATH- 

    Jacob Price

    PhD Defense, May 31 at 10am, HUB 337

    Advisor: Panos Stinis

    Multiscale Techniques for Nonlinear Dynamical Systems: Applications and Theory

 and at about the same time as NARC

   Krithika Manohar

   PhD Defense, May 31 at 1pm, HUB 250

   Advisors: Nathan Kutz, Steve Brunton

   Data-Driven Sensor Placement Methods

as well as the Thursday seminar at 3:30 in Lewis 208 (more below). There is also the Data Visualization poster session presentation (12 -2 in the CSE Atrium).

Also don't forget to sign up for the new NARC email list:  https://mailman1.u.washington.edu/mailman/listinfo/narc. We will be discontinuing the old google group after this quarter. 

Thanks!

May 31:  3:30-4:30 Fred Wan Conference Room, Lewis Hall 208

Speaker: Saverio Eric Spagnolie
         University of Wisconsin

Title: Active matter invasion of a viscous fluid and a no-flow theorem

Abstract:

Suspensions of swimming bacteria in fluids exhibit incredibly rich behavior,
from organization on length scales much longer than the individual particle
size to mixing flows and negative viscosities.  We will discuss the dynamics
of hydroddynamically interacting motile and non-motile stress-generating
swimmers or particles as they invade a surrounding viscous fluid, modeled
by coupled equations for particle motions and viscous fluid flow.  Depending
on the nature of their self-propulsion, colonies of swimmers can either
exhibit a dramatic splay, or instead a cascade of transverse concentration
instabilities as the group moves into the bulk.  An active slender-body
approximation will be introduced and used in a linear stability analysis
of concentrated line distributions of particles, matching the results of
our full numerical simulations.  Along the way we will prove a very
surprising "no-flow theorem": particle distributions initially isotropic
in orientation lose isotropy immediately but in such a way that results in
no fluid flow *anywhere* and *at any time*.