Research And Application For Partition Curve Of Hydraulic Radius Of Non-uniform Rough Open-channel Flows

Study on partition curve of hydraulic radius in open-channel flows has always been one of the important topics in hydraulics research.However,most scholars have studied the partition curve of hydraulic radius for smooth or uniform rough open channels,and There are relatively few scholars who study the partition curve of hydraulic radius in non-uniform rough open channels,Based on the basic theory of modern fluid mechanics,a simple form equation of partition curve of hydraulic radius is proposed for open-channel flows.The equation is consistent with the existing results in a smooth open channel or uniform rough open channel.The method is simple in form and more clear physical meaning.Corresponding to the exponential velocity distribution formula,a formulas of the average sidewall and bed shear stress in open-channel flows,the formula of the average flow velocity and resistance coefficient of open-channel flow,and the formula of the composite roughness of open-channel flow are derived.which are compared with the existing experimental data.1.Based on the simple form of exponential velocity distribution formula,assuming there is a partition curve of hydraulic radius in open-channel flow,open channel is divided into three regions,and the velocity in the vertical direction with the wall obeys the law of exponential velocity distribution,and partition curve of hydraulic radius were deduced,who were compared with Einstein and Yang Shuqing.2.Based on the basic theory of partition curve of hydraulic radius of open-channel flows.Expressions of the boundary shear stress and average sidewall and bed shear stress in non-uniform rough open channel,and it is compared with the existing experimental data.The result shows that the formula for the shear stress of the non-uniform rough open channel obtained in this paper is more accurate and reliable than the formula derived by Yang Shuqing.3.Based on the partition curve of hydraulic radius,this paper derives the formula of the average velocity and resistance coefficient of the non-uniform rough open channel according to the exponential flow distribution formula.The average flow velocity formula under wide open channel condition is verified and analyzed.A comparison of the average flow velocity formula with the experimental data show relatively small error4.In this paper,based on the partition curve of hydraulic radius in open-channel flows,according to the law of conservation of flow and Manning's formula,the formula of comprehensive roughness in non-uniform rough open channel is derived and verified with the collected experimental data.The results show that the formula of this paper are in good agreement with the measured data,and can be used in practical engineering and water tank experiments.