Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Past events in this series


Thu, 21 Nov 2024

12:00 - 13:00
L3

Tension-induced giant actuation in elastic sheets

Dr. Marc Suñé
(Mathematical Institute)

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Abstract

Tension-induced giant actuation in elastic sheets

Dr. Marc Suñé

Buckling is normally associated with a compressive load applied to a slender structure; from railway tracks in extreme heat to microtubules in cytoplasm, axial compression is relieved by out-of-plane buckling. However, recent studies have demonstrated that tension applied to structured thin sheets leads to transverse motion that may be harnessed for novel applications, such as kirigami grippers, multi-stable `groovy-sheets', and elastic ribbed sheets that close into tubes. Qualitatively similar behaviour has also been observed in simulations of thermalized graphene sheets, where clamping along one edge leads to tilting in the transverse direction. I will discuss how this counter-intuitive behaviour is, in fact, generic for thin sheets that have a relatively low stretching modulus compared to the bending modulus, which allows `giant actuation' with moderate strain.

Thu, 05 Dec 2024

12:00 - 13:00
L3

Chaotic flows in polymer solutions: what’s new?

Prof. Rich Kerswell
(University of Cambridge)

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Further Information

Rich Kerswell is a professor in the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the University of Cambridge. His research focuses on fluid dynamics, particularly in the transition to turbulence, geophysical fluid flows, and nonlinear dynamics. Kerswell is known for studying how simple fluid systems can exhibit complex, chaotic behavior and has contributed to understanding turbulence's onset and sustainment in various contexts, including pipes and planetary atmospheres. His work integrates mathematical modeling, theoretical analysis, and computational simulations to explore instabilities and the fundamental mechanisms governing fluid behavior in nature and industry.

Abstract

It is well known that adding even small amounts of  long chain polymers (e.g. few parts per million) to Newtonian solvents can drastically change the flow behaviour by introducing elasticity. In particular,  two decades ago, experiments in curved geometries  demonstrated  that polymer flows can be  chaotic even at vanishingly small Reynolds numbers. The situation in `straight’ flows  such as pressure-driven flow down a channel is less clear  and hence an area of current focus. I will discuss recent progress.