Influence Of Sediment Concentration And Diameter On Flow Characteristics

The Yellow River is a sandy river and its sediment,sediment concentration,is the most of many rivers in the world,because of its flowing through the soft soil,weak ability to resist impact,treat water easy to collapse under the condition of Loess Plateau,easy to form high sediment concentration in the flood,the water has a large carrying capacity,can occur in a short period of strong erosion,arrive in the downstream of wide and shallow river,the sediment settling velocity drop and make the sediment silt up,and the river bed will rise to form the overhanging river,increased river management works.The limit sediment concentration that can be reached by the tributaries of the middle reaches of the Yellow River varies greatly from north to south,and the limit sediment concentration in the tributaries in the north is greater than that in tributaries in the south.This paper mainly studies the characteristics of the sediment laden flow.Firstly,the trends,abrupt changes and periodicity of the measured flow of the tributaries of the middle reaches of the Yellow River,the amount of sediment discharge,and the annual maximum sediment concentration are analyzed to found that typical sediment change law of water in the middle reaches of the Yellow River from viscous experiment was carried out in mechanism research.The rotary viscometer was used to carry out the viscosity tests for different sediment concentrations of different sand samples,and the effects of sediment concentration and sediment particle size on the flow characteristics of sediment laden flow were analyzed.The following conclusions are obtained: 1 Sediment suspension viscosity increased with the increase of sediment concentration,the different samples,the same viscosity trend along with the change of sediment concentration,but the degree of change,the suspension viscosity than the particle size of sediment particle size smaller than thick viscous suspension;2 The smaller the median particle size of sediment is,the smaller the sediment grain diameter.Withthe increase of sediment concentration,the particle size has more and more influence on the viscosity;3 The ultimate shear force becomes larger with the increase of sediment content,and the sediment content of the suspended sediment with fine particle size is less than that of the coarser sediment in the Bingham body;4 In the same sand sample,he change trend of the sediment suspension viscosity of each group is basically the same,the viscosity of the smaller size is larger than that of the coarser particle size;5 The maximum sediment concentration of suspended sediment with smaller particle size is smaller than that of coarse particle size.This study has deepened the mechanism of sediment production in the middle reaches of the Yellow River,and can provide technical support for the prevention and control of soil erosion in the middle reaches.