Preliminary Study On The Model Similarity Law Of Water Flow With The Suspended Sediment Under The Effect Of The Seabuckthorn Plant

Serious soil erosion led to severe soil and water loss and thus extremely various ravines crossbar within the soft rock area.The seabuckthorn plant flexible dam is a type of ecological measure being able to effectively prevent soil and water loss in the soft rock area.In order to economically plant the seabuckthorn plant flexible dam,it is necessary to design it according to the water flow data within the gully.However,on this situation,it is impossible to carry out on-site observation for every gully within the soft rock area to achieve the data,which is impractical.Nevertheless,we can design the model experiments according to the similarity theory of fluid mechanics discipline to predict the water flow data for the prototype gully,which can overcome the deficiency of lacking data for the prototype gully so as to provide the initial theoretical proof for the plan and plantation of the seabuckthorn flexible dam.Therefore,it is extremely necessary and meaningful to conduct the research on the model similarity law for the water flow with the suspended sediment and the similarity scale.Based on these above,firstly,the author reviewed a large number of research results of the plant's effect on the water flow with the suspended sediment and the similarity law for the suspended sediment model.Secondly,on the basis of the model similarity principle,the author analyzed the similarity scales between model and prototype as well as their relationship.Thirdly,the similarity principle between model and prototype was analyzed and discussed according to the differential equation for the kinetic incompressible fluid.Fourthly,based on the similarity theory and its principles,the author deduced the model similarity law for the water flow with the suspended sediment according to the kinetic and dynamic equations for the water flow with sediment under the effect of the seabuckthorn plant.Fifthly,we calculated the similarity scales for the water flow with sediment under the seabuckthorn plant effect.Lastly,based on the experimental data and the set similarity scale,the author deduced and calculated the proximate data of the water flow parameters for the prototype gullies(the east gully and the west gully)under the effect of the seabuckthorn flexible dam,on the condition of the different discharges and the same plant dam length and width as well as the various plantation parameters of the seabuckthorn flexible dam,which includes the water depth,the cross-sectional averaged velocity,the vertical velocity and the cross-sectional sediment concentration,and their lengthwise variation characteristics and tendency were thus analyzed.The study can provide the theoretic evidence and reference for the preliminary design of the seabuckthorn flexible dam on the prototype gully within the soft rock region,and it has important practical meaning.The main results are as follows:1.According to the similarity scale of the flow,the dam length and dam width,the author calculated the similarity scale of the velocity,the water depth,the sediment concentration and the vertical velocity on the prototype gully;2.According to the similarity theory and its principles,the author deduced the model similarity law for the water flow with the suspended sediment according to the kinetic and dynamic equations for the water flow with sediment under the effect of the seabuckthorn plant;3.According to the experimental data and similarity scale in the experimental area,the author deduced and calculated the proximate data of the water flow parameters for the prototype gullies(the east gully and the west gully)under the effect of the seabuckthorn flexible dam,on the condition of the different discharges and the dam length,which includes the water depth,the cross-sectional averaged velocity,the vertical velocity and the cross-sectional sediment concentration;4.According to the data of water flow,water depth,the cross-sectional sediment concentration under the effect of the various length of seabuckthorn flexible dam,the author analyzed their lengthwise variation characteristics.The results show that the suitable dam length shall be selected during the design of the prototype gullies of seabuckthorn plant flexible dam;5.By analyzing the same plant dam length and width as well as the various plantation parameters of the seabuckthorn flexible dam,the water depth,the cross-sectional averaged velocity,and the cross-sectional sediment concentration of the prototype gullies,the results show that the set parameters of the 4#model test bed can effectively provide the theoretic reference for the preliminary design of the seabuckthorn flexible dam on the prototype gully(the east gully and the west gully).