Dynamics of SeSPs in a sea of sheared disks

We study the motion of superellipse sector particles (SeSPs), two-dimensional curved particles that parameterize corner sharpness, aspect ratio, and opening aperture. Some shapes that SeSPs encompass include discs, rods, convex "stars", and C- and U-shaped concave particles. In our study, a small number of SeSPs (with 180° openings and an annular shape) are surrounded by a monolayer of monodisperse hard disks in a 360° annular-planar shear cell that allows for arbitrarily large simple shear. The number of SeSPs is kept small (to minimize SeSP-SeSP interactions), all particles are tracked with video analysis, and we analyze the translational and rotational mean-squared displacements of all particles. To analyze how SeSPs impact the structure and motion of the background disks, we examine radial density and bond orientation distribution functions and nonaffine motions. We compare these quantities for disks near and far from SeSPs and, when SeSPs approach one another, their rate of approach and relative orientation.