Random walk simulation of organic particle sedimentation process in the open channels
CHEN Xiao1, LIU Zhao-wei1, CHEN Yong-can1,2
1. State Key Laboratory Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;
2. College of Environment and Resources, Southwest University of Science and Technology, Mianyang 621010, China
Based on the main characteristics of open channel flows, this research built a random walk model for fine particles within the inhomogeneous open channel turbulence, with modifications concerning influences of the vertical inhomogeneity of turbulence intensity and loitering effect. Using the established model, the sedimentation loss of fine particles in the open channels was simulated. Simulation results showed that, when influence of the loitering effect was not considered, particle sedimentation loss rate could be calculated by the ratio of particle settling velocity to the water depth; when influence of the loitering effect was considered, particle sedimentation loss rate would have a 18%~27% reduction compared to quiescent environments. The reduction percentage was basically consistent with the asymptotic value of declining percentage of particle settling velocity (19%~25%) in the homogeneous turbulent fields. The conclusion of this article was mainly based on two premises that the resuspension of particle was not considered, and the loitering effect was the dominant mechanism of turbulence on particle settling. Proposed method and results can be applied to calculate the sedimentation process of particles to the channel bottom more accurately.
陈啸, 刘昭伟, 陈永灿. 明渠中有机质微粒沉降过程的随机游走模拟[J]. 中国环境科学, 2020, 40(11): 4813-4820.
CHEN Xiao, LIU Zhao-wei, CHEN Yong-can. Random walk simulation of organic particle sedimentation process in the open channels. CHINA ENVIRONMENTAL SCIENCECE, 2020, 40(11): 4813-4820.
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