Study On The Movement Of Fine Particles Bed Load On Armor Layer

The stochasity of bed load has been a key research topic for more than several decades,which is important and challenging.The stochastic motion of bed load particles eventually results from the uncertainty and complexity of bed load armor layer.Clusters existing on the coarsen bed belong to a kind of special microform,after gravel bed surface was scoured by flows.Clusters become more stable than single cobble and shades finer particles,which lead to gravel bed resisting erosion apparently,while high speed region among clusters could aggravate entrainment of finer particles.Accordingly clusters have effects on the transportation of sediments.In order to find and study the relations between them and bed load transport rate,it is necessary to analyze the transportation of bed load quantitatively using Digital Image Processing Technique(DIPT)in the controlled flume.In order to get the motion element(displacement,speed,angle)data,we use Digital Image Processing Technique(DIPT)to track 3mm colored bed load sediment movement based on Lagrange method with the controlled flume.Get statistical characteristics of sediment movement parameters(the velocities,step lengths,step times and waiting times)The results shows that:1.Wide graded sand pebble bed in water erosion under prone morphology of the aggregates throughout the armor layer.2.Coarsen bed has important effect on the fine particles bed load movement.The cluster will shield sediment movement but the tunnel will accelerate the movement of sediment particles and then it will affect the transport rate.3.The particle sediment movement process has obvious intermittent.4.The sediment in different size has different velocity distribution.5.The cluster lead to non-uniformity of the surface of the bed and anisotropy.It has significant influence on the direction of motion of fine particles bed load.