2:00–3:00 pm
KPTC 206 5720 S Ellis Ave
Suspensions with Internal Degrees of Freedom: From the Lab to the Ocean
The dynamics of particles in viscous fluids are ubiquitous in both nature and industry. When driven externally (via applied forces) or internally (via intrinsic activity), these particles exhibit intriguing, far-from-equilibrium collective behaviors. In this seminar, I will explore two topics in driven suspensions: (1) the Stokesian sedimentation of shaped particles in laboratory settings,1, 2 where particle geometry gives rise to an effective Hamiltonian, overturning the classic instability of spheres;3 and (2) the fluid-structure interactions of marine snow observed during ocean expeditions, which reveal hidden viscoelastic degrees of freedom arising from biological mucus,4 suggesting significant modifications to oceanic carbon flux and storage estimates.5 By contrasting these complementary scientific approaches — one conducted in the controlled environment of the laboratory and the other in the dynamic and complex field setting of the ocean, I will present my research vision, highlighting the immense potential of conducting soft matter physics at sea. My work aims to deepen our understanding of suspension dynamics within the ocean's biological pump and to inform the development of ocean-based carbon removal technologies. In doing so, I seek to cultivate a research practice that bridges disciplines and
settings.
- R. Chajwa, N. Menon, S. Ramaswamy, Phys. Rev. Lett. 122, 224501 (2019).
- R. Chajwa, N. Menon, S. Ramaswamy, R. Govindarajan, Phys. Rev. X 10, 041016 (2020).
- J.M. Crowley, Journal of Fluid Mechanics, 45(1):151-159 (1971).
- R. Chajwa, E. Flaum, K.D. Bidle, B.V. Mooy, M. Prakash, Science 386, eadl5767 (2024).
- B. B. Cael, Lionel Guidi, Science 386, 149-150 (2024).
Speaker: Dr. Rahul Chajwa, Stanford University
Host: Prof. Heinrich Jaeger, Dept. of Physics (jaeger@uchicago.edu)