Numerical investigation of angular particle dynamics

Suspended particles in fluid flows are typically modeled as spheres due to their isotropic properties, which simplify the resolution of particle shape, dynamics, and kinematics. While existing literature has extensively studied spheroidal particles that can either be prolate(rod-shaped) or oblate(disk-shaped), natural sediment grains often exhibit angularity. These edges as well as the non-isotropic shape can lead to different dynamic and kinematic behaviors compared to non-angular particles. In this study, we model angular particles as octahedrons using the Immersed Boundary Method. The first part of the study involves direct numerical simulations of oscillatory flow over a bed of angular particles to compare stress distributions with those over spherical beds. The second part examines the dynamic behavior differences among spherical, spheroidal, and octahedral particles in steady flow. Initial results indicate that octahedral particles exhibit more pronounced angular oscillations than spheroidal particles. Additionally, particle layout significantly influences rotation statistics, with upstream particle wakes affecting the torque on downstream particles.

 

HPC at UTD and TACC are acknowledged for providing computational time.