專題演講 Seminar

2026/05/15(Fri) 10:30 -12:00 一樓演講廳 1F, Auditorium

Title

Elastohydrodynamics of flexible filaments: instabilities, chaos and attractors

Speaker

David Saintillan (Mechanical and Aerospace Engineering, University of California San Diego)

Abstract

Elastic filaments and semiflexible polymers are ubiquitous in both biology and engineering, where they play a key role in cell mechanics and locomotion and are the constituents of many non-Newtonian fluids. In this talk, I will discuss the dynamics of elastic filaments in microscale fluid flows, with focus on buckling instabilities that arise when viscous stresses overcome bending rigidity in the presence of thermal fluctuations. In a compressional flow, elastoviscous buckling occurs and is found to give rise to helicoidal morphologies at large values of the elastoviscous number, a dimensionless measure of flow strength relative to elasticity. We characterize this phenomenon using a combination of numerical simulations, reduced-order modeling, and microfluidic experiments using actin filaments. In simple shear flow, the rotational component of the flow contributes to a series of morphological transitions with increasing elastoviscous number, where the tumbling motion seen in weak flows gives way to elastoviscous buckling followed by a tank-treading regime in stronger flows. Finally, I will conclude by analyzing filament dynamics in oscillatory flows, where the emergence of quasi-reversible states and chaotic attractors is uncovered.

Language

演講語言 (Language): in English

Hosted by

施宏燕 助研究員
Shih, Hong-Yan / Assistant Research Fellow