Turbulence Characteristics And Bottom Sediment Transport In Open Channel

In the paper, the dynamic motion of bed load transport is set up on the base of force analysis and its mechanical characteristics of sediment movement .The process calculation of bed load transport is also researched. In order to verify the bed-load transport rate which is set up in the paper, the experimental study on the action between coarse sediment and open channel flow is carried out in the laboratory flume.The incipient motion of coarse sediment ,the formation and development of sand ripples ,bed load transport and its characteristic of turbulent flow in open channel are measured and researched systematically in laboratory flume with Acoustic Doppler Velocitimeter(ADV).Based on the tool of turbulence statistical theory, the turbulent characteristics such as the fluctuating intensity, turbulent kinetic energy ,Reynolds stress,velocity probabi1ity density,spectrum density,skewness coefficient and kurtosis coefficient are measured and researched .Besides, quasi-ordering structures in turbulent flow were also studied with correlation analysis.The interaction between fine sediment and turbulent flow is compared and researched by comparison with coarse sediment. In order to make further study, the reological characteristic and its influence factor is researched and Bingham shear stress obtained from reological experiment can be applied to estimate critical incipient shear stress.The effect of pipeline on incipient motion of sediment and bed load transport is also researched on base of above research, in which the pipeline is studied as the disturbance of sediment movement.