The Movement And Nonlinear Analysis Of Sediment Particle

The study on the laws of flow and sediment transport was the core content ofrivers, and the analysis of single sediment particle motion was the foundation ofsediment microscopic properties. Therefore, the research of a single sediment particlewas important and significance both in theory and practical engineering.Two phase flow model of flow and sediment was analyzed in this paper, then thestatus of research on chaos and its application of sediment were summarized. Theforces on rigid particles moving in relation to fluid having been studied, a generalform of equation for discrete particles motion in arbitrary flow field is obtained.The stability for single sediment particle in turbulent flows was studied by thenonlinear dynamic methods, the stable conditions for the periodic stationary rollmotion were ascertained, and the jump phenomena are explained analytically. It isfound that the amplitude of particle motion could have mutations, even under asmaller flow turbulence frequency. Under some conditions, the small changes ofsediment particle size or the flow turbulence frequency could also cause the mutationof movement amplitude.Considering bottom flow structure and the random position of non-uniformSediment on the bed, formulas for calculating the incipient velocity of non-uniformsediment was established by using the rolling model. The results show that thevalidity of the formula was verified by experiment data. The factors effecting theincipient motion of cohesive fine sediment were analyzed in the view ofhydrodynamic conditions, cohesive sediment composition and structure, the researchstatus of incipient motion of cohesive sediment was summarized systematically, andfurther research methods were discussed.Expression of related factors infecting the vertical distribution of sedimentconcentration was obtained through the dynamics analysis of sediment verticalmovement.The results show that with the increase of the friction velocity, theconcentration curve increasingly steep, that the concentration well distributed.And with the increases of particle diameter, density and friction velocity，concentrationsof inflection point became higher.