| As new type weirs,both tooth type weir and Z type weir can not only be used to retain and discharge water,but also have good landscape effect.However,at present there are few researches on the flow characteristics of the tooth type weir and t no results have been seen for the Z type weir,which cause them to have no design basis in practical engineering.Therefore,this thesis deduces the following results through theoretical research: the flow formula of tooth type weir by using the energy equation and the flow formula of the Z type weir based on dimensional analysis.What’s more,their flow characteristics and discharge capacity are also studied through physical modeling experiment.A preliminary study on flow characteristic of tooth type weir and Z type by theoretical analyses,physical model experiment is carried out in this thesis.In the aspect of theory analyses,the flow formula of the tooth type weir is derived by using the energy equation,based on dimensional analysis,the flow formula of the curved weir is derived.In the aspect of physical model experiment,the flow characteristics and discharge capacity of the tooth type weir and Z type weir studied experimentally under in the different type and hydraulic parameter.Firstly,research the flow pattern and give the water line of tooth type weir and velocity profile of weir;And then,the flow coefficient of different tooth type weirs and Z type weirs and the influence factors of the weir are contrasted and analyzed,and the formula for calculating the comprehensive discharge coefficient of the tooth type weir and Z type weir is also worked out.Comprehensive the above research,the main research results include:(1)In the case of free flow,the flow of tooth type weir is similar to sharp-crested weir with the weir flow stable and the flow of the downstream channel equally distributed.The flow of Z type weir is relatively complex,and the distribution of water flow in the downstream channel is not equal.(2)The discharge capacity of tooth type weir is smaller than linear orthogonal weir,and the discharge capacity become lager while the tooth height and tooth width become lager.The discharge capacity of Z type weir is slightly larger than linear orthogonal weir when they are in the same weir width and length ratio.(3)According to the research,main factors affecting the tooth type weir is weir height ratio,tooth width and tooth height;main factors affecting the Z type weir is weir head and height ratio,weir width and length ratio.In this paper,the influence of different factors will be discussed in detail.(4)In the case of free flow,considering the influences of various factors on the discharge coefficient,the formula for calculating the integrated discharge coefficient of tooth type weir and Z type weir are obtained by using the method of statistical analysis. |
