Λεπτομέρειες βιβλιογραφικής εγγραφής
| Τίτλος: |
Two settling spheres in a tube at intermediate fluid inertia. |
| Συγγραφείς: |
Lai, Zenan1 (AUTHOR), Nie, Deming1 (AUTHOR) nieinhz@cjlu.edu.cn |
| Πηγή: |
Physics of Fluids. Jul2026, Vol. 38 Issue 7, p1-18. 18p. |
| Θεματικοί όροι: |
*Particle dynamics analysis, *Vortex shedding, *Drag coefficient, *Fluid dynamics, *Lattice Boltzmann methods |
| Περίληψη: |
Three-dimensional lattice Boltzmann simulations were performed to study the gravity-driven settling and interaction of two heavy spheres (density ratio 1.5) in a square tube (the width of the tube is five times the sphere diameter) at 140 ≤ Ga (Galileo number) ≤ 240, approximately corresponding to 160 < ReT (terminal Reynolds number) <310. Three distinct motion regimes are identified: steady motion (Ga ≤ 160), irregular helical motion (175 ≤ Ga ≤ 195), and regular helical motion (200 ≤ Ga ≤ 240). The onset of unsteadiness occurs at 160 < Ga < 165, slightly higher than for a single sphere, indicating that sphere–sphere interaction enhances effective confinement and suppresses wake instability. Irregular helical motion is marked by frequent circling direction reversals, strong inter-sphere separation fluctuations, and synchronized double-threaded vortex shedding. At Ga ≈ 225, a sharp wake transition from double-threaded to loop-like hairpin vortices coincides with a sudden increase in helical frequency and horizontal hydrodynamic force. Symmetric initial conditions yield consistent steady or regular helical motion, while irregular helical motion shows initial-position path dependence. Drag coefficients follow the order: two spheres > single sphere > unconfined sphere. These results reveal the strong coupling between sphere–sphere interaction, wall confinement, and wake topology in determining unsteady particle dynamics at intermediate fluid inertia. [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: |
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