All Publications


  • Purcell's swimmer in a shear-thinning fluid PHYSICAL REVIEW FLUIDS Qin, K., Pak, O. 2023; 8 (3)
  • Reinforcement learning of a multi-link swimmer at low Reynolds numbers PHYSICS OF FLUIDS Qin, K., Zou, Z., Zhu, L., Pak, O. 2023; 35 (3)

    View details for DOI 10.1063/5.0140662

    View details for Web of Science ID 000942071400015

  • Propulsion of an elastic filament in a shear-thinning fluid SOFT MATTER Qin, K., Peng, Z., Chen, Y., Nganguia, H., Zhu, L., Pak, O. 2021; 17 (14): 3829-3839

    Abstract

    Some micro-organisms and artificial micro-swimmers propel at low Reynolds numbers (Re) via the interaction of their flexible appendages with the surrounding fluid. While their locomotion has been extensively studied with a Newtonian fluid assumption, in realistic biological environments these micro-swimmers invariably encounter rheologically complex fluids. In particular, many biological fluids such as blood and different types of mucus have shear-thinning viscosities. The influence of this ubiquitous non-Newtonian rheology on the performance of flexible swimmers remains largely unknown. Here, we present a first study to examine how shear-thinning rheology alters the fluid-structure interaction and hence the propulsion performance of elastic swimmers at low Re. Via a simple elastic swimmer actuated magnetically, we demonstrate that shear-thinning rheology can either enhance or hinder elastohydrodynamic propulsion, depending on the intricate interplay between elastic and viscous forces as well as the magnetic actuation. We also use a reduced-order model to elucidate the mechanisms underlying the enhanced and hindered propulsion observed in different physical regimes. These results and improved understanding could guide the design of flexible micro-swimmers in non-Newtonian fluids.

    View details for DOI 10.1039/d0sm02130j

    View details for Web of Science ID 000631581600001

    View details for PubMedID 33885447