A Study On Hydraulic Characteristics Of Ditch With Inflow Along The Way

With the rapid development of urbanization in China,there are serious problems in the field of rain and flood control in many cities.The area of urban hardening is increasing constantly,which leads to the decrease of seepage capacity of the underlying surface of the original site and the inability of rain water to penetrate in time,urban flooding is a frequent problem.As a typical urban drainage system,the linear drainage system has been widely used in the urban drainage system.The study of the hydraulic characteristics of an inflow ditch along the channel has a significant impact on the design of the entire drainage system.The inflow ditch along the channel belongs to the Nullah system and is a uniform flow.Therefore,it is obvious that the Xie Cai formula for uniform flow in open channels can not be directly applied,otherwise,the calculation error may seriously affect the drainage caused by a large amount of water on the road surface,or the channel size is not reasonable and cause waste.At present,there are few researches on the flow calculation of non-uniform flow in open channel and the law of water surface curve,and the current pavement drainage design standard needs to be improved.This paper introduces the exploration and development prospect of non-uniform flow in open channel with inflow at home and abroad,using the method of theoretical analysis,model experiment and computer simulation,based on the analysis of the flow process and the water surface curve in the channel with inflow along the channel,the influence of the roughness height of the wall,the slope of the channel and the width of the channel bottom on the flow velocity and the water depth in the channel are systematically studied.It is expected to provide reference for the design and calculation of road drainage pipe and canal in China.The main research contents are as follows:In terms of theoretical analysis,according to the existing norms and literature,using MATLAB drawing method,an example of calculating the water surface curve of uniform inflow along the river based on Xie Cai formula is given,it is shown that the Xie Cai formula recommended in the current code can not be directly used to calculate the water surface curve of open channel system with an inflow channel along the course.Furthermore,the water surface curve formula(?)of open channel with an inflow channel along the course is derived from Adhémar Jean Claude Barréde Saint-venant’s differential equation,a numerical example is given to show that the curve obtained by this method is in good agreement with the curve obtained by the experiment.In the aspect of experimental research,a special uniform inflow experimental platform was set up to measure the water depth of different channel bottom width,discharge,gradient and rough height of wall,and draw the corresponding water surface curve,research finds that traffic uses a function(?)It has a good fitting effect.It is concluded that the variation rate of water depth increases with the increase of slope,the roughness height of wall and the variation rate of water depth along the same discharge.In the aspect of numerical simulation,the hydraulic characteristics of the channel with inflow are simulated and analyzed by using software FLURNT,and the obtained water surface curves agree with the trend of theoretical calculation and experimental results.