SoP Nonlinear Science Seminar

Abstract: We present experiments on the effects of laminar flows on the motion of swimming microbes and on the spreading of the excitable Belousov-Zhabotinsky chemical reaction. A universal theoretical framework of active mixing predicts invariant manifolds -- “burning invariant manifolds” (BIMs) for front propagation and “swimming invariant manifolds” (SwIMs) for self-propelled tracers -- that act as one-way barriers for both of these systems. In fact, the problem of front propagation is a special case of the more general, active mixing theory. We present results from several experiments: (a) BIMs blocking reaction fronts in a range of 2-D and 3-D vortex-dominated flows; (b) SwIMs blocking motion of swimming bacteria and eukaryotic microbes in a microfluidic hyperbolic flow in a cross channel; and (c) on-going experiments about the behavior of swimming microbes in vortex flows.

Bio: Prof. Solomon is a professor in the Department of Physics & Astronomy at Bucknell University in central Pennsylvania. He and his undergraduate research students study chaotic fluid mixing and the effects of fluid mixing on dynamical processes occurring in the flows. Their experiments at Bucknell have been funded by 7 grants from the National Science Foundation and Research Corporation, and have resulted in 30 publications. The research program was recognized by the American Physical Society in 2005 for outstanding research by an undergraduate and in 2014 for outstanding research by a faculty member at an undergraduate institution.