The Motion Of Suspended-load And Its Effects On The Structure Of Flow

The sediment-laden flow fluctuating velocimeter designed in this study has a well static and dynamic charateristic. The system of signal treatment may be used to calculate various one-dimentional. statistical factors by computer. This system of measurement and analysis may prove to be beneficial, to the investigation of turbulent structure of the sediment-laden flow.The mean velocity profile of sediment-laden flow can bet divided into two regions. The profiles for both regions follow the logarithmic law. Only the Von Karman universal constants are different from each other. EveiL the velocity profile of the pseudo one-phase flow consisting of neutrally buoyant particles also follows the same tendency, and is utterly different from that of the homogeneous flow. The maim factors affecting the velocity profiles are the viscosity near the bed, particle grid resistance and the density gradient. Formulas of the mean velocity profiles of the two regions can be developed on the basis of this physicalmodel, and the expression of the Von Karman universal, constant is given with an error of less than 15 % .The distribution of concentration still obeys the diffusion law, only the efftects of the group particle fall velocity and the dispersive force on the diffusion index Z1 shall be considered. Generally, Z1 is a function of the height y .The turbulent intensity and frequency of the sediment-laden flow are less than those of the clear water flow, but the fundamental structure of the flow remains unchanged.The frictional resistance of the sediment-laden flow is essentially the same as that of the clear water flow within the range of size distribution of sediment used in our experiments.