Interaction between a pair of particles settling in a stratified fluid
A Doostmohammadi1, A M Ardekani
1Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 17, 2013
Summary
Fluid stratification alters particle interactions, causing attraction between side-by-side settling particles. This density gradient modifies tandem settling behaviors, replacing typical tumbling with separation phenomena.
Area of Science:
- Fluid dynamics
- Multiphase flow
- Particle dynamics
Background:
- Anisotropic structures in fluidized suspensions depend on particle microstructures.
- Particle microstructure is dictated by the dynamics of particle pair interactions.
Purpose of the Study:
- To numerically simulate particle interactions in linearly stratified fluids.
- To investigate how fluid stratification affects particle pair dynamics compared to homogeneous fluids.
Main Methods:
- Numerical simulation of particle interactions.
- Analysis of particle pair dynamics under varying stratification strengths.
Main Results:
- Stratification induces attraction between particles settling abreast, driven by buoyancy, inertia, and diffusion.
- Tandem particle settling is altered; the "drafting-kissing-tumbling" behavior shifts to "drafting-kissing-separation" or "drafting-separation."
- Weak stratification leads to prolonged "kissing" and reduced reorientation rates, with buoyancy-induced vortices and stratified jets governing interactions.
Conclusions:
- Fluid stratification fundamentally changes particle pair interaction dynamics.
- Buoyancy-induced vortical structures and stratified jets are key mechanisms in stratified fluid particle dynamics.
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