Swimming in Complex Fluids

Abstract

We review the literature on swimming in complex fluids. A classification is proposed by comparing the length and time scales of a swimmer with those of nearby obstacles, interpreted broadly, extending from rigid or soft confining boundaries to molecules which confer the bulk fluid with complex stresses. A third dimension in the classification is the concentration of swimmers, which incorporates fluids whose complexity arises purely by the collective motion of swimming organisms. For each of the eight system classes which we identify we provide a background and describe modern research findings. While some classes have seen a great deal of attention for decades, others remain uncharted waters still open and awaiting exploration.

31 pages, 13 figures, to appear in Annual Review of Condensed Matter Physics

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Cited by in corpus (16)

• A review of active matter reviews
• The 2024 Motile Active Matter Roadmap
• Deforming Active Droplets in Viscoelastic Media
• A nematic liquid crystal with an immersed body: equilibrium, stress, and paradox
• Generalized Three-Sphere Microswimmers
• Self-diffusiophoretic propulsion of a spheroidal particle in a shear-thinning fluid
• Dynamics of magnetoelastic robots in water-saturated granular beds
• Effective and efficient modeling of the hydrodynamics for bacterial flagella
• Micro-swimmer collective dynamics in Brinkman flows
• Active nematic response to a deformable body or boundary: elastic deformations and anchoring-induced flow
• Levitation and dynamics of bodies in supersaturated fluids
• Bidirectional Zigzag Growth from Clusters of Active Colloidal Shakers
• Micro-swimmer locomotion and hydrodynamics in Brinkman Flows
• Undulatory swimming in suspensions and networks of flexible filaments
• A swimming bacterium in a two-fluid model of a polymer solution
• Corkscrew motion of Trypanosoma brucei is driven by helical beating of the flagellum and facilitated by its bent shape