Paper Number
AB20 

Session
Active and Biological Materials

Title
Giant vesicle dynamics in large amplitude oscillatory extension

Presentation Date and Time
October 13, 2021 (Wednesday) 10:15

Track / Room
Track 2 / Ballroom 7

Authors (Click on name to view author profile)

  1. Lin, Charlie (Purdue University, Davidson School of Chemical Engineering)
  2. Kumar, Dinesh (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)
  3. Ritcher, Channing (University of Illinois as Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
  4. Wang, Shiyan (Purdue University, Davidson School of Chemical Engineering)
  5. Schroeder, Charles M. (University of Illinois at Urbana-Champaign, Chemical and Biomolecular Engineering)
  6. Narsimhan, Vivek (Purdue University, Davidson School of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Charlie Lin1, Dinesh Kumar2, Channing Ritcher2, Shiyan Wang1, Charles M. Schroeder2 and Vivek Narsimhan1
1Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907; 2Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801

Speaker / Presenter 
Lin, Charlie

Keywords
experimental methods; computational methods; biological materials; microfluidics

Text of Abstract
While the behavior of fluid vesicles in steady flows have been studied extensively, how time-dependent oscillatory flows impact the shape dynamics of vesicles is not as well understood. In this presentation, we present our results on the nonlinear dynamics of vesicles in large amplitude oscillatory extensional (LAOE) flows from both experiments and boundary integral (BI) simulations. Our results characterize the transient membrane deformations, dynamical regimes, and stress response of vesicles in LAOE in terms of reduced volume (vesicle asphericity), capillary number (Ca, dimensionless flow strength), and Deborah number (De, dimensionless flow frequency). We find that results from single vesicle experiments agree well with BI simulations across a wide range of parameters. We group our results into dynamical regimes based on vesicle deformation characteristics: the pulsating, reorienting, and symmetrical regimes. The distinct dynamics observed in each regime result from a competition between the flow frequency, flow time scale, and membrane deformation timescale. By calculating the particle stresslet, we quantify the nonlinear relationship between average vesicle stress and strain rate. Additionally, we present results on tubular vesicles that undergo shape transformation over several strain cycles. Broadly, this work provides new information regarding the transient dynamics of vesicles in time-dependent flows that directly informs bulk suspension rheology. We will also present some preliminary work on the dynamics of multicomponent vesicles.