城市雨洪内涝三维实景动态模拟表达方法研究

Research on the expression method of three dimensional real scene dynamic simulation of urban rain flood waterlogging

受全球气候变暖、城市化进程加快的共同影响,近年来城市极端降雨事件频发导致内涝灾害发生。基于水文、水动力模型得到的城市雨洪数值模拟结果难以展示降雨、内涝渐变过程等问题。提出雨洪内涝过程三维实景动态模拟表达方法,首先采用GAST(GPU Accelerated Surface Water Flow and Transport Model)水动力模型对雨洪内涝过程数值模拟,通过Godunov类型有限体积法进行数值离散,采用GPU并行技术加速计算获取不同输出时间下的数值模拟结果,创新设计了GAST模型数值模拟结果与数字高程模型数据耦合方法,构建了数字淹没网格模型(Digital Inundation Grid Model,DIGM),基于WebGL和三维地理信息系统(3D Geographic Information System,3D GIS)技术开发三维实景动态可视化引擎,构建雨洪内涝过程三维实景动态渲染机制,对雨洪内涝过程三维实景动态模拟进行表达。最后,采用本方法实现了西安2020年7月10日2次强降雨致涝过程三维实景动态模拟表达,结果生动直观准确,与实测结果吻合度高,表明该方法可有效弥补现有城市雨洪内涝数值模拟表达方法的不足,具有良好的应用价值。

Affected by global warming and accelerated urbanization,extreme rainfall events in cities have occurred frequently in recent years,resulting in waterlogging.The numerical simulation results of urban stormwater based on hydrological and hydrodynamic models are difficult to show the problems of rainfall and waterlogging gradation.Firstly,the GAST hydrodynamic model is used to simulate the stormwater waterlogging process,the numerical discretization method is carried out by Godunov type finite volume method,the GPU parallel technology is used to accelerate the calculation to obtain the numerical simulation results under different output times,the numerical simulation method of the GAST model and the digital elevation model data coupling method is innovatively designed,and the digital inundation grid model is constructed Model),based on WebGL and 3DGIS technology,develop a 3D reality dynamic visualization engine,build a 3D reality dynamic rendering mechanism for the rainwater waterlogging process,and simulate the dynamic 3D reality scene of the stormwater waterlogging process.Finally,the three-dimensional dynamic simulation expression of the second heavy rainfall waterlogging process in Xi'an on July 10,2020 is realized by this method,and the results are vivid,intuitive and accurate,and the degree of agreement with the measured results is high,indicating that this method can effectively make up for the shortcomings of the existing numerical simulation expression methods of urban stormwater waterlogging,and has good application value.