2025/08/06 by Harish Mirajkar, Shekhar, Chandra, Piotr Zdybel +6
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Material Dynamics and Properties #Micro and Nano Robotics #Pickering emulsions and particle stabilization #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.2508.15783
openalex publication_date 2025/08/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This work investigates experimentally and numerically the dynamics of rigid particles settling under gravity in a highly viscous fluid. We demonstrate that certain shapes: cones, crescent moons, arrowheads, and open flat rings reorient and approach a stationary configuration. We determine the mobility coefficients and the characteristic reorientation times. We find out that the two rotational-translational mobility coefficients have opposite signs. Therefore, based on the equations of motion for rigid bodies with two orthogonal planes of symmetry, theoretically derived by Joshi and Govindarajan, Phys. Rev. Lett., 134, 2025, 014002 and Ekiel-Jezewska and Wajnryb, J. Phys. Condens. Matter, 21, 2009, 204102, we conclude that the approached stationary configurations are stable. Owing to the similarity principle, our experimental findings apply to micro-objects in water-based solutions. The reorientation of sedimenting rigid particles of certain shapes to a stationary stable configuration in a relatively short time might be used for biological, medical, or industrial applications.