Study On The Influence Of Golden Mussel On The Water Conveyance Capacity Of Channel

The South-to-North Water Diversion Project has alleviated the uneven distribution of water resources in China,but it will be invaded by fouling organisms.These organisms attach to the surface of the channel and grow with high density,which have caused serious impact on the water diversion project.Golden mussel is the most common and grows in large quantities on the side wall of the channel.The appearance of golden mussel has an influence on the water conveyance construction,which is mainly reflected in the decrease of cross section area,the increase of roughness and the decrease of water conveyance efficiency.Many scholars have carried out researches on the biological habits of golden mussel and put forward a series of ecological management measures,but there are still many blind spots in the research on the influence of golden mussel on the water conveyance capacity of channels.In order to solve the problem of the influence of golden mussel on the water conveyance capacity of channel,this paper simulates the channel with golden mussel growth by roughening the trapezoidal channel side wall.and controls the hydraulic parameters such as the distance between the rough bodies,the opening of the tail gate and the flow rate,studies the variation law of the channel hydraulic characteristics(water depth,velocity,roughness,etc.)and the correlation among the hydraulic elements,and analyzes the influence of the golden mussel on the flow movement.The results of this paper are as follow.(1)The changes of tailgate opening,flow rate and roughness spacing have certain influence on water flow movement.The water blocking capacity increases with the decrease of the distance between the roughened bodies.When the discharge is greater than the critical flow,the amplitude of water depth changes suddenly increases and the step depth appears.Since the energy loss includes not only the energy of water flow to overcome the resistance loss of rough body,but also the energy loss of flow through trapezoidal channel to the rectangular pool in front of tailgate,the observed roughness value is larger than the theoretical value.(2)By analyzing the relationship between specific energy and hydraulic factors,it is found that the hydraulic factors which cause the increase of water depth in slow flow will indirectly lead to the increase of section specific energy,and the specific energy ofsection is positively correlated with roughness.(3)The vertical velocity distribution of the same section and the vertical velocity distribution of different sections after roughening are analyzed respectively.It is found that the influence of roughness and backwater on the vertical velocity is different.Compared with logarithmic formula,parabola formula can better fit the vertical velocity.(4)By analyzing the relationship between friction velocity,wall shear stress and various hydraulic factors,it is found that the hydraulic factors leading to the increase of hydraulic radius will lead to the increase of friction velocity and wall shear stress,and the roughness increases with the increase of wall shear stress.(5)The order of relative turbulence intensity in the different directions is longitudinal relative turbulence intensity,transverse relative turbulence intensity and vertical relative turbulence intensity;the closer to the rough body and channel bottom,the greater the relative turbulence intensity.Finally,based on the previous research on golden mussel,combined with the results of this experiment,the influence of golden mussel on water conveyance channel is analyzed.