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

Abstract

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 + =11.3. 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. particle cluster, preferential concentration, low-speed streak, coherent structure, large eddy simulation, Lagrangion trajectory method Citation:Lu H, Wang B, Zhang H Q, et al. Analysis of solid particle clusters in coherent structures of turbulent channel flow. Sci China Tech

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