Analysis of solid particle clusters in coherent structures of turbulent channel flow

• Published in: Science China. Technological sciences Vol. 56; no. 10; pp. 2525 - 2530
• Main Authors: Lu, Hao, Wang, Bing, Zhang, HuiQiang, Qin, JianXiu, Wang, XiLin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2013
• Subjects: Channel flow; Clusters; Coherence; Engineering; Fluid dynamics; Fluid flow; Lycopodium; Marine; Progress of Projects Supported by NSFC; Streak; Turbulence; Turbulent flow; 固体颗粒; 拉格朗日; 摩擦速度; 条纹结构; 槽道; 湍流相干结构; 粒子流; 集群分析; Lagrangion trajectory method; particle cluster; large eddy simulation; low-speed streak; preferential concentration; coherent structure
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-013-5336-9

A particle-laden turbulent channel flow is investigated to study particle clusters in large-scale turbulent coherent structures. The fluid phase is calculated by large eddy simulation and particles are tracked using Lagrangian trajectory method. The flow Reynolds number is 180 based on the friction velocity and half-width of the channel. The particle is lycopodium with St=0.93 which may well follow the fluid phase. The mean and fluctuating velocities of both two phases are obtained, which are in good agreement with previous data. The strongest accumulations of particles in low-speed streak structures are observed at y~=l 1.3. Moreover, once particles are captured in low-speed streaks, most of them will reside there for a long period. Particles clustered in low-speed streaks obtain smaller instantaneous wall-normal and spanwise velocities than those out of there, which induce a larger particle flux into low-speed streaks than that out of there. The study is important for understanding particle dispersion mechanisms in gas-particle turbulent channel flows.