Direct Numerical Simulation of Multiple Particles Sedimentation at an Intermediate Reynolds Number
Deming Nie 1, Jianzhong Lin 2*, Mengjiao Zheng 11 Institute of Fluid Mechanics, China Jiliang University, Hangzhou, 310018, China.
2 Institute of Fluid Mechanics, China Jiliang University, Hangzhou, 310018, China; State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China.
Received 27 May 2013; Accepted (in revised version) 13 March 2014
Available online 24 June 2014
In this work the previously developed Lattice Boltzmann-Direct Forcing/Fictitious Domain (LB-DF/FD) method is adopted to simulate the sedimentation of eight circular particles under gravity at an intermediate Reynolds number of about 248. The particle clustering and the resulting Drafting-Kissing-Tumbling (DKT) motion which takes place for the first time are explored. The effects of initial particle-particle gap on the DKT motion are found significant. In addition, the trajectories of particles are presented under different initial particle-particle gaps, which display totally three kinds of falling patterns provided that no DKT motion takes place, i.e. the concave-down shape, the shape of letter ``M" and ``in-line" shape. Furthermore, the lateral and vertical hydrodynamic forces on the particles are investigated. It has been found that the value of Strouhal number for all particles is the same which is about 0.157 when initial particle-particle gap is relatively large. The wall effects on falling patterns and particle expansions are examined in the final.AMS subject classifications: 76T20, 76-02, 76M28
PACS: 47.11.-j, 47.57.ef, 47.57.E-, 47.55.-t
Key words: Lattice Boltzmann method, sedimentation, fictitious domain, falling pattern.
Email: firstname.lastname@example.org (D. Nie), email@example.com (J. Lin), firstname.lastname@example.org (M. Zheng)