粘性细颗粒泥沙静水絮凝-沉降模拟

针对实验观测黏性细颗粒泥沙絮凝沉降过程存在困难的问题,在考虑泥沙絮团分形特性和曲线轨迹碰撞的前提下,建立了静水絮凝-沉降模型,并验证了模型的正确性,最后根据模拟试验结果分析了絮团体积分布及絮团平均粒径的时空变化和絮团分形维数对模型的影响。研究结果表明:不同深度下,大粒径絮团的体积和絮团的平均粒径均随时间遵循先增后减的规律,但随着深度的增加,絮团体积分布变宽,大粒径絮团所占比重增加,絮团平均粒径的最大值增加且出现时间较早;分形维数越大,竖直方向的泥沙输移作用越强。

Simulation of flocculation-settling for cohesive fine sediment in still water

Since it was difficult to observe the process of flocculation and settling for cohesive fine sediment, this paper presented a model for the flocculation and settling process of cohesive fine sediment in still water, and checked the model with previously published data. At last, temporal and spatial variation of volume distribution and average diameter of flocs were studied through a series of simulated experiments, as well as the impact of fractal dimension on this model. The results revealed that the volume of large flocs and average diameter of flocs appeared the trend from increasing to decreasing as time increased, but with the depth increasing, the range of floc volumes broadened, the ratio of large flocs increased, and the maximum of average diameters became larger with appearing early. The effect of sediment transport in vertical direction became stronger as the fractal dimension increased.