A Voronoi analysis of preferential concentration in a vertical channel flow

作者：Nilsen Christopher^*; Andersson Helge I; Zhao Lihao

来源：Physics of Fluids, 2013, 25(11): 115108.

DOI：10.1063/1.4830435

• Core region
• Downward flow
• Inertial particles
• Particle clustering
• Particle velocities
• Preferential concentration
• Stokes number
• Vertical channels

We use three-dimensional Voronoi analysis and results from a direct numerical simulation to study the preferential concentration of inertial particles in a vertical channel flow at Reynolds number 395. By comparing results in upward and downward flows with results from a channel flow without gravity, we are able to determine how gravity affects the particle clustering. Gravity increases the drift of particles towards the walls in an upward flow, while in the downward flow more particles are transported to the centre of the channel. For particles with Stokes number 100, the mean wall-normal particle velocity is positive in the entire core region. A significant increase in variance of the Voronoi probability distribution in the core region is observed in downward flow for Stokes numbers 30 and 100, indicating stronger particle clustering than in upward flow or flow without gravity. The increased clustering in the downward flow is believed to be partly caused by the reversed wall-normal drift assisting in bringing particles close together in the centre of the channel.

• 出版日期2013-11