| The study of flood movement law in the Jianghu system can be divided into three methods: mathematical model calculation,physical model experiment and field observation analysis.Numerical simulation method is widely used in practical engineering because of its advantages of low cost,short modeling time,high efficiency and convenient modification of calculation parameters.Especially with the development of computer technology,graphics and multimedia technology progress,the research results of integrated hydrodynamic numerical model and visual analysis are emerging.However,due to the lack of real-time calculation and visualization of flood inundation range for high-resolution Jianghu system,it still has limitations in the practical application of water conservancy industry.Therefore,this paper takes hydrodynamic model and visualization technology as the starting point to study and analyze the calculation efficiency of hydrodynamic model of high-resolution Jianghu system,and based on this,the visualization method of hydrodynamic numerical simulation results is studied.Finally,based on Web GIS technology,the real-time online calculation and visualization system of river flood is developed.The main research results of this paper are summarized as follows:(1)Taking Jingjiang Dongting Lake system as the research area,Mike21 software and classic semi implicit Euler Lagrange hydrodynamic model are selected as typical two-dimensional explicit and implicit hydrodynamic models in plane to test and analyze the efficiency of two-dimensional numerical simulation of River Lake flood.The results of the model rate determination show that the accuracy of the plane two-dimensional hydrodynamic model based on the high resolution computing grid is improved compared with the traditional mathematical model of the river network in the past.In addition,the stability of the two-dimensional semi implicit model is better when simulating the flow movement of large-scale Jianghu system,and the calculation efficiency can reach more than 38 times of the explicit model.(2)According to the efficiency evaluation results of two-dimensional hydrodynamic model and the investigation results of one-dimensional hydrodynamic model,the advantages and disadvantages of different dimensions hydrodynamic models are compared.The adaptability analysis of real-time online calculation and visualization of river flood is carried out by various models.The results show that the efficiency of the two-dimensional semi implicit model can not meet the requirements of real-time calculation and visualization in practical application,while the one-dimensional semi implicit hydrodynamic model can keep high accuracy and the calculation efficiency is far higher than that of the two-dimensional semi implicit model.Therefore,the paper combines the calculation results of one-dimensional hydrodynamic model with the high-resolution two-dimensional unstructured grid to display the flood inundation range data connection mode,taking into account the real-time calculation efficiency of one-dimensional model and the high precision of the two-dimensional unstructured grid,which greatly improves the flow of visualization process while satisfying the calculation efficiency.(3)Based on the data connection between the results of one-dimensional model and two-dimensional mesh,a new algorithm for constructing closed wet surface is proposed.The water level of all sections is calculated by one-dimensional hydrodynamic model,and the water level values of all two-dimensional grids between sections are obtained by interpolation of water level of adjacent sections;Then,based on the topological relationship between one-dimensional section and two-dimensional unstructured grid,a new algorithm for flood inundation composite area is proposed.In addition,according to the boundary between the combined regions and the coordinate points on the boundary of the combined area,a low resolution submerged area construction algorithm is proposed.The results show that the algorithm can improve the flow of visualization process.(4)Based on springboot framework,Vue framework and Web GIS technology,the evolution system of river and river flood is developed.From the perspective of system requirements,the system function system and operation flow are designed,and the appropriate computer technology is selected to build the framework of the system.The paper describes the encapsulation method of hydrodynamic model and various algorithms,and the interaction between front and rear data.The development process and details of the front-end module are discussed.Finally,taking the actual topographic data and flow conditions of Jingjiang Dongting Lake area as an example,the functions of each module of the river lake flood evolution system are introduced.The demonstration results show that the system can simulate the dynamic flood process of large-scale river system. |
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