摘要
The flow instability is related to many engineering problems and belongs to a wide-ranging research field. When the problem on the transition from the laminar to the turbulence caused by the instability of the laminar is studied,the "neutral line" and the critical Reynolds number are always taken as the criterion to judge whether a certain kind of flow is stable,whose corresponding flow medium is the clear water,that is,the single-phase Newtonian fluid. And it is not studied in the traditional in-stability theory that the hyper-concentration flow widely exists in rivers. This shortage can be covered by this research. Study shows that the instability of non-Newtonian fluid such as hyper-concentration fluid,compared with Newtonian fluid such as clear water,is influenced by not only Reynolds number,the ratio of the inertia force and the viscous force,but also many other factors such as the sediment concentration,the concentration distribution,the grain size,the volu-metric weight of the sediment and so on,which make the mechanical principle even more complex. So the results of the research can supply the scientific basis for the explanations of "slurrying river",the turbulence intensity of the flow carrying sediment and the variance of the turbulence structure.
The flow instability is related to many engineering problems and belongs to a wide-ranging research field. When the problem on the transition from the laminar to the turbulence caused by the instability of the laminar is studied, the “neutral line” and the critical Reynolds number are always taken as the criterion to judge whether a certain kind of flow is stable, whose corresponding flow medium is the clear water, that is, the single-phase Newtonian fluid. And it is not studied in the traditional instability theory that the hyper-concentration flow widely exists in rivers. This shortage can be covered by this research. Study shows that the instability of non-Newtonian fluid such as hyper-concentration fluid, compared with Newtonian fluid such as clear water, is influenced by not only Reynolds number, the ratio of the inertia force and the viscous force, but also many other factors such as the sediment concentration, the concentration distribution, the grain size, the volumetric weight of the sediment and so on, which make the mechanical principle even more complex. So the results of the research can supply the scientific basis for the explanations of “slurrying river”, the turbulence intensity of the flow carrying sediment and the variance of the turbulence structure.
基金
the National Natural Science Foundation of China (Grant No 40776045)
the National Basic Research Program of China (973 Program) (Grant No 2007CB714101)
the Ministry of Education's New Century Elitist Project of China
