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Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
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Interaction between two unequal particles at intermediate Reynolds numbers: A pattern of horizontal oscillatory
Deming Nie1, Geng Guan1, Jianzhong Lin2
1Institute of Fluid Mechanics, China Jiliang University, Hangzhou, China.
Physical Review. E
|February 19, 2021
Summary
This study used the lattice Boltzmann method (LBM) to simulate two interacting particles in a vertical channel. Researchers identified distinct settling regimes and a novel horizontal oscillatory motion (HOM) pattern.
Area of Science:
- Fluid dynamics
- Computational physics
- Particle dynamics
Background:
- Understanding particle interactions in fluid flows is crucial for various industrial and natural processes.
- The behavior of multiple particles settling under gravity is complex and depends on numerous parameters.
Purpose of the Study:
- To investigate the settling dynamics of two interacting particles with varying densities and diameters in a vertical channel.
- To identify transition boundaries between separate and interacting particle settling regimes.
- To characterize a newly observed horizontal oscillatory motion (HOM).
Main Methods:
- Two-dimensional lattice Boltzmann method (LBM) simulations.
- Systematic variation of particle density ratio (λ) and diameter ratio (r).
- Analysis of particle trajectories, terminal velocities, and oscillation characteristics.
Main Results:
- Identified power-law relationships for transition boundaries between settling regimes.
- Revealed a horizontal oscillatory motion (HOM) pattern for specific diameter ratios and intermediate Reynolds numbers.
- Observed that oscillation magnitude decreases with increasing density ratio (λ), while frequency increases.
- Noted a transition from drafting-kissing-tumbling to HOM with increasing λ.
- HOM can bifurcate to a vertical steady state under certain conditions.
- A critical confinement ratio was found to influence particle interaction patterns.
Conclusions:
- The study elucidates complex settling behaviors of binary particles, including a novel HOM.
- Transition boundaries and the emergence of HOM are predictable based on particle size and density ratios.
- Confinement effects play a significant role in dictating particle interaction dynamics.
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