Numerical simulation of the sedimentation of cylindrical pollutant particles in fluid

Article type: Research Article

Authors: Lin, Jian-zhong | Wang, Ye-long | Wang, Wei-xiong | Yu, Zhao-sheng

Affiliations: Department of Mechanics, Zhejiang University, Hangzhou 310027,China, E-mail:[email protected] | Department of Mechanical and Mechatronic Engineering, the University of Sydney,NSW 2006, Australia

Abstract: The sedimentation of cylindrical pollutant particleswhich fall through a fluid is investigated. Differing from previous research work, particle oscillation and effect of particle on thefluid are considered, and the torque exerted on a particle whenviscous fluid flow around a particle is got through experiment andincluded in the numerical simulation. The computational results showed that the sedimentation velocities of particle increase slowly with the increase of particle aspect ratio . For disk-like particle, when the motion direction of particle is parallel to axis of particle, particle falls more slowly than the case ofperpendicular to axis of particle; while for rod-like particle, itis inverse. For sedimentation of a crowd of high-frequency oscillating cylindrical particles with arbitrary initialorientation, both vertical velocity and horizontal velocityoscillate dramatically, the degree of oscillation of the former is stronger than the later. A crowd of particles fall more quicklythan an isolated particle. Particles tend to strongly align in thedirection of gravity. The computational results agreed well withthe experimental ones and helpful for controlling of pollutant particles.

Keywords: cylindrical pollutant particles, sedimentation, orientation, velocity, numerical simulation

Journal: Journal of Environmental Sciences, vol. 14, no. 4, pp. 433-438, 2002