Abstract:

The interaction of fluids and electric fields is at the heart of natural phenomena such as the disintegration of raindrops in thunderstorms and many applications such as ink-jet printing, microfluidics, crude oil demulsification, electrospray ionization in mass spectrometry, even space propulsion. Many of these processes involve droplets and there has been long-standing interest in understanding drop electrohydrodynamics.

In this talk I will overview some intriguing phenomena involving viscous drops: symmetry-breaking instabilities in strong fields due to the Quincke rotation effect (droplet pancake-like flipping, formation of belt of vortices

around the drop equator), streaming from the drop equator that creates visually striking ""Saturn-rings"" around the drop, non-axisymmetric ""kiss-and-run” interactions of a drop pair, and drop motion due to enclosed active particles propelled by the Quincke effect. These complex behaviors arise from nonlinear dynamics in the Stokes flow regime that is yet to be fully understood.

 

Biography:

Petia M. Vlahovska received a PhD in chemical engineering from Yale (2003) and MS in chemistry from Sofia University, Bulgaria (1994). She was a postdoctoral fellow in the Membrane Biophysics Lab at the Max Planck Institute of Colloids and Interfaces and spent ten years on the faculty at Dartmouth College and Brown University, before joining the faculty at Northwestern University in 2017. Her research is in fluid dynamics, membrane biophysics, and soft matter. Dr. Vlahovska is the recipient of David Crighton Fellowship (2005), NSF Career Award (2009) and a Humboldt Fellowship (2016). In 2019, she was elected fellow of the American Physical Society.