2020/07/31 by Zaiyi Shen, Shen, Zaiyi, Juho S. Lintuvuori +1
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Micro and Nano Robotics #Particle Dynamics in Fluid Flows #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft) #cond-mat.soft #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.2007.16142
arxiv created 2020/07/31 · openalex publication_date 2020/07/31 · arxiv updated 2020/08/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the dynamics of torque driven spherical spinners settled on a surface, and demonstrate that hydrodynamic interactions at finite Reynolds numbers can lead to a concentration dependent and non-uniform crystallisation. At semi-dilute concentrations, we observe a rapid formation of a uniform hexagonal structure in the spinner monolayer. We attribute this to repulsive hydrodynamic interactions created by the secondary flow of the spinning particles. Increasing the surface coverage leads to a state with two co-existing spinner densities. The uniform hexagonal structure deviates into a high density crystalline structure surrounded by a continuous lower density hexatically ordered state. We show that this phase separation occurs due to a non-monotonic hydrodynamic repulsion, arising from a concentration dependent spinning frequency.