黄河泥沙架桥絮凝体分形结构的动态演变研究

黄河泥沙架桥絮凝试验研究表明 ,剪切絮凝条件下泥沙絮凝体的最佳絮凝结构只能维持一段时间。在整个剪切絮凝过程中 ,泥沙絮凝体的分形结构从疏松多孔、开放的分枝状DLCA构造 ,逐步演变到密实的最佳RLCA构造后 ,又开始呈现疏松脆弱结构。絮凝体分维值上升至某一值后 ,又以微小的幅度下降。停止搅拌后 ,泥沙絮凝体粒径能在瞬间长大 ,但絮团结构脆弱稀疏 ,分维值低

Study on dynamic evolution of fractal structure of bridging flocculated sand aggregates in Yellow River

Shear-induced sand bridging flocculated settling experiment is conducted for Yellow River and the result indicates that the lifetime of optimal structure will be limited for a certain duration. During the whole shear flocculation stages, the dynamic evolution process of fractal structure of sand aggregates is observed that the fractal structure can change from loose and open-branching DLCA structure to compact RLCA structure little by little. However, the structure begins to become loose as flocculation process continues. The fractal dimension value of aggregates increases to an optimum value gradually and then begins to decrease slowly with small extent. When stirring is stopped, the size of sand aggregates grows immediately and the floc structure becomes weak and thin. As a result, the fractal dimension value of aggregates is low.