GALCIT Colloquium

Friday February 28, 2020 3:00 PM

Particle hydrodynamics near deformable interfaces

Speaker: Bhargav Rallabandi, Mechanical Engineering, UC Riverside
Location: Guggenheim 133 (Lees-Kubota Lecture Hall)

Interactions of suspended particles with interfaces are important in many natural and engineered

systems including examples in lubricated bearings, blood flow and microfluidics. In the first part of my

talk, I will discuss a microfluidic application that uses ultrasound-driven bubbles to either sort or trap

microparticles by size. I will present a predictive model that shows that particle sorting and trapping

result from an interplay between the particle's inertia and hydrodynamic interactions with the

oscillating bubble interface. I will go on to discuss limiting cases of strong and weak interactions which

recovers results from geometry and acoustics, respectively. The second part of the talk addresses

situations where interface deformation, mediated by hydrodynamic interactions, is a direct

consequence – and a subsequent cause – of particle motion. I will present experiments demonstrating

that rigid particles translating near a flexible elastic membrane are repelled by it due to hydrodynamic

interactions. A model of these interactions involving membrane tension and bending will then be

discussed, leading to a general framework for particle hydrodynamics near interfaces and soft

substrates. The results suggest that similar interactions may play a role in blood flow and cellular

processes at the micron scale.

Series GALCIT Colloquium Series

Contact: Benedikt Barthel bbarthel@caltech.edu