| Movement law of flow is one of the most basic problem in mechanics of sediment transport. Sediment particle begin to move at the action of the flow.but it effect the flow itself during the course of moving, in nature river, sediments is it move in the form of suspended sediments mainly, it have close contacts with size of particle to move to suspend, Speaking from the mechanics angle , suspended sediments move and suspend due to flow turbulence, subsided by the action of gravity. So particle suspend depend on the characteristic of turbulence mainly. Sediment particle size be suspended have direct connections with turbulence function, the flow turbulence intensity determine sediment particle size , and sediment particle size act on the turbulence intensity, too. It is significance to researching sediment particles' move for deeply knowledging the inner mechanics of sediment transport and suspend and promoting the development of sediment theory.In the paper , theory analyzed and experimentation research are adopted. Systemly researched the sediment influences distributed law of the velocity of flow,suspended characteristic of suspended sediment partilces and effction ingredients ,During the course of experimence, a three-dimensional MicroADV(Acoustic Doppler Velocimeter) is carried on in this paper, and measure the distribution of time-mean velocity in sediment-laden flow, offering the thereunder for exact calculating flow turbulence intensity.Because influencing each other between the sediment particle and flow structure and this kind of complicated change influencing each other under different hydraulic condition, the velocity of flow is distributed differently in clear water and in sediment-laden flow.At the beginning, we researched the formula structure of the distribution of velocity of flow according to the experimental data in sediment-laden flow, pointed out that the drawbacks in the existing formula of exponential of velocity distribution and verifying the formula,the general form of exponential of velocity distribution has been established, and test the formula by the experimental data, the result was very well. What's more, researched the index and coefficient of the exponential of velocity distribution, found the closed relation between the two parameters with intensity of flow and sediment concentration. It was analyzed that the influence of interaction between sediment particles and flow to the distribution of velocity of flow with different sediment condition and flow intensity. Based on verifying the existing distribution formula application by the experimental data, a new formula of exponential of velocity distribution was proposed, at the same time, the variational law of coefficient and index in the new formula with sediment concentration, diameter of particles and hydraulic condition is analyzed, It has been concluded that coefficient increases with increasing sediment concentration,hydraulic condition and diameter of particles; However index decreases with increasing diameter of particles, and increases with increasing sediment concentration.The difference of the formula of the distribution of velocity in clear flow and in sediment-laden flow is mainly because the flow inner structure effected by the variation of sediment and hydraulic condition.Exerimental results indicate that there is a law of sediment particles size, i.e., sediment particle size along depth (whether bed face upward to surface of water since) decreasing law when the sediment particle size is relatively larger. Thinner particle does not have the law or the phenomenon, because they wash qualities of rushing down, it is suspended and transfered swimming all the time. It have studied the distribution law along depth of sediment particles under sediment concentration, sediment particles size and hydraulic condition, shown that: sediment particles sorting not only closely related to sediment concentration, hydraulic condition and sediment particles one's own relevant, Particle sorting varies with the above three kinds of conditions: the sediment particles size increase with increasing sediment concentration, with increasing hydraulic condition, with increasing sediment particle oneself. So is flow turbulence?, The big or small and even degree of sediment and particle is an important factor of influence particle sorting ?Sediment particles is Suspended in the sediment-laden flow because of the flow turbulence, and setting due to gravity action. Inherent motive force that the sediment particle suspended —the flow turbulence? Above the discussion, one have studied inherent relation between sediment particles size and the flow turbulence intensity along depth ? Show that sediment particle size and the flow turbulence intensity along to consistency better in y/h>0.1 along depth0 Namely general speaking, no matter sediment particle size or the flow turbulence intensity along depth, which increase with increasing distance from the position to bedc Fanaly,according to test materials , establish relation between middle size of sediment particles and flow turbulence intensity at the one position along depth.
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