2013/10/11 by Alison E. Koser, Koser, Alison E., Nathan C. Keim +3
Engineering · Materials Science · Physics and Astronomy · #Characterization and Applications of Magnetic Nanoparticles #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Micro and Nano Robotics #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1310.3212
videos included
openalex publication_date 2013/10/11 · arxiv created 2013/11/06 · arxiv updated 2013/11/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Many fascinating phenomena such as large-scale collective flows, enhanced fluid mixing and pattern formation have been observed in so-called active fluids, which are composed of particles that can absorb energy and dissipate it into the fluid medium. In order to investigate the role of hydrodynamic interactions in the collective behavior of an active fluid, we choose a model system: paramagnetic particles submerged in water and activated by an oscillating magnetic field. The magnetic field induces magnetic attractions among the paramagnetic particles, activating the particles, and injecting energy into the fluid. Over many cycles, the particles aggregate together and form clusters. In order to form clusters, however, the particles must overcome viscous drag. We investigate the relative roles of viscosity and magnetism. When the role of viscosity is important, the particles cannot form large clusters. But when the role of magnetism is important, the particles rapidly form organized, large clusters. Our results shown in this fluid dynamics video suggest that viscous stresses slow the clustering rate and decrease the size of clusters in a self-assembling colloidal system.