Numerical simulation of square shaped particle sedimentation

Direct numerical simulations of square particle sedimentation in a viscous incompressible fluid are presented to examine the effects of sharp edges for various particle-to-fluid density ratios and different initial inclination angles. The settling process exhibits four different motion regimes; non-oscillatory, non-uniform centered oscillatory, uniform off-centered oscillatory, and non-uniform off-centered (irregular) oscillatory. At moderate density ratios, we observe that the rotational motion of settling square particle varies with the initial inclination angle. We employ Dynamic Time Warping and Fast Fourier Transform to analyze translational and angular velocities. Oscillating systems are described using phase-space plots, and a chaotic phenomenon is observed at a higher density ratio.(c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.