中文摘要：

黏性泥沙絮团的形成机理和沉降特性对河口海岸细颗粒泥沙运动规律研究具有重要作用。为了从微观结构出发研究絮团运动机理，由扩散受限絮凝体聚集模型生成不同大小的分形絮团，引入格子Boltzmann方法模拟三维分形絮团的静水沉降，获得了絮团沉速的变化过程。比较格子Boltzmann算法模拟结果与采用盒子计数分维数的Winterwerp絮团沉速公式，发现二者有较好的一致性，表明格子Boltzmann模拟方法可应用于河口海岸环境中的黏性泥沙运动研究。

英文摘要：

The complicated fractal flocculation processes and settling behavior of cohesive sediment are very important to understand the cohesive sediment transport in estuaries and along coasts. The mud fractal floc is formed by using the diffusion limited cluster-cluster aggregation model. The 3-D fractal mud floc settling in quiescent water is simulated by introducing the Lattice Boltzmann method and the evolution of the settling velocity of single mud floc is obtained. The simulation result well agrees with the Winterwerp settling velocity formula. It shows that the Lattice Boltzmann method is a new approach to explore the cohesive sediment transport in estuarine and coastal water flow.