Experimental Research On The Influence Of Fishing Nets On Flood Discharge Capacity Of Wide And Shallow River

With the development of social economy, the popularity of fish aquaculture has gradually improved. Large-scale fish aquaculture will affect the flow regime, water level and flow rate nearby. If the area occupied by fish aquaculture takes up too much in the river, It will adversely affect the flood-discharge capacity of the river. On the one hand, to their own needs, the fishermen expand the scale of fishing nets. On the other hand, many rivers carrying navigation, flood discharge and other features, ensuring flood-discharge capacity of those rivers would play an important role in protecting cities and towns, industry and agriculture, lives and properties of people on both sides of those rivers.In this paper, the method of combining theoretical analysis with experimental study was used to analyze the hydraulic model experiment of the Huaihe river, a series of experiments were conducted according to the area of fish aquaculture on the downstream side of Shao Bo lake in the Huaihe River. To study the effect of fishing nets to flood discharge capacity of the wide and shallow rivers and provide reference for flood safety and river regulation of the Huaihe River. Scientific realign the scale of fishing nets, protect the legitimate rights and interests of fishermen, promote the sustainable development and utilization of rivers and lakes and promote the stable development of China’s society and economy.The main research results are:1. The making theory of the Huaihe river physical model, the experimental methods, the materials and test equipment are mainly discussed, the simulation of fishing nets and related processes are briefly introduced.2. According to the mechanics of fluid resistance, the calculation formula of fishing nets impact on river comprehensive roughness was deduced. The influence of the Reynolds number, the density of nets and the direction of flowing water on the fishing nets resistance is analyzed.3. From three aspects including the water level, flow regime and flow velocity, there is a research on the influence of the flood discharge capacity of wide and shallow river.(1) In the aspect of water level, the water level of site which is close to the upstream of fishing nets will be significantly improved, to the opposite, the water level will be dropped in the downstream of fishing nets. Therefore, it is necessary to pay close attention to the water level in the upstream of fishing nets in a larger flow.(2) In the aspect of flow velocity, both the width and length of fishing nets have a significant effect on the flow velocity outside, and the flow velocity inside depends on the type and layers of fishing nets. For this reason, the width and length of fishing nets should not be too wide or too long for the stable of the flow velocity.(3) In the aspect of flow regime, the existence of fishing nets will make flow regime instability. Especially in the case of the larger flow, when the angle of fishing nets and flow direction is small, Vortex appears around fishing nets which has an impact on the safety of river navigation.