城市洪涝数值模拟技术研究

发布时间：2018-05-14 01:25

本文选题：城市洪涝 + 排水模型　；参考：《华南理工大学》2015年博士论文

【摘要】：在全球气候变化背景下,随着我国社会经济的快速发展和城市化水平的不断提升,城市洪涝灾害发生更加频繁,造成的经济损失和社会影响也较以往更加严重。城市洪涝数值模拟对科学合理地规划和设计排水体系,提高城市洪涝灾害控制和管理水平以及有效地减少洪水造成的生命财产损失具有非常重要的意义。目前,我国在城市洪涝数值模拟技术方面研究还不够深入和系统,难以为城市洪涝灾害管理提供有效的支持。因而,研究城市洪涝数值模拟问题具有很重要的现实意义和应用价值。本文以城市洪涝为对象,基于水动力学方法,研究了城市洪涝数值模拟计算方法,主要的研究工作和成果如下:(1)建立了一维明满流模型。采用Preissmann四点隐式差分格式对明满流控制方程进行离散求解,建立了一维明满流数值模型,可以同时模拟明渠流和压力流以及二者的共存和过渡状态。为了提高模型计算效率,避免求解大型稀疏矩阵,将节点水位迭代法进行改进后从明渠流推广到明满流的应用中。采用一系列不同算例分别从不同方面对一维明满流数值模型进行了验证,证明了模型具有处理实际洪水,处理明渠流和压力流,处理环状与树状管网等方面的能力以及具有良好的计算精度。(2)建立了二维地表水动力模型。基于非结构网格中心型的有限体积法,采用Godunov型格式计算界面通量,并将分片线性逼近的MUSCL格式应用于变量重构,建立了一个时空均具有二阶精度的二维水动力学模型。为了提高二维模型的稳定性和计算效率,将隐式的双时间步算法引入到水动力学中,使得模型在处理城市洪水时更加高效和稳定。采用一系列算例对二维水动力模型处理恒定流,处理间断流,处理动边界以及处理实际地形等方面的能力进行了检验与验证,证明了模型具有良好的精度和收剑速度,能够有效地处理干湿边界问题,能够满足和谐性要求,能够处理复杂水流以及城市建筑物和实际地形,算法的鲁棒性较好,稳定性和效率都较显式格式有大幅度提升。(3)建立了一二维耦合的城市洪涝模型。分别采用经验公式和相互提供边界条件的方式建立了一二维模型地表侧向连接和正向连接,并提出了一种新的计算垂直方向水流交换的方法,在此基础上建立了地表地下耦合的城市洪涝数值模型。采用两个水平连接算例和一个垂向连接的理想算例分别对耦合模型进行了检验,结果表明模型具有良好的精度,满足水量守恒的要求。通过将模型应用于深圳市区民治水库溃坝洪水风险分析和广州新河浦社区暴雨洪水计算,并得出了较为合理的结果,证明了本文建立的一二维耦合的模型具有处理实际地形和实际问题的能力,能够应用于城市洪涝数值模拟计算。
[Abstract]:Under the background of global climate change, with the rapid development of China's social economy and the continuous improvement of urbanization level, urban flood disasters occur more frequently, resulting in more serious economic losses and social impacts than in the past. Numerical simulation of urban flood is of great significance for scientifically and reasonably planning and designing drainage system, improving the control and management level of urban flood disaster and effectively reducing the loss of life and property caused by flood. At present, the research on urban flood numerical simulation technology in China is not deep enough and systematic, and it is difficult to provide effective support for urban flood disaster management. Therefore, the study of urban flood numerical simulation has important practical significance and application value. In this paper, based on the hydrodynamic method, the numerical simulation method of urban flood is studied. The main research work and results are as follows: 1) the one-dimensional open-flow model is established. The Preissmann four-point implicit difference scheme is used to discretize the open-flow control equation. A one-dimensional open-flow numerical model is established to simulate the open channel flow and pressure flow, as well as the coexistence and transition states of the two flows at the same time. In order to improve the computational efficiency of the model and avoid solving the large sparse matrix, the node water level iteration method is improved and extended from open channel flow to open full flow. A series of examples are used to verify the one-dimensional open-flow numerical model from different aspects. It is proved that the model can deal with actual flood, open channel flow and pressure flow. The 2-D surface hydrodynamic model is established, which is capable of dealing with annular and tree-shaped pipe networks and has good calculation accuracy. Based on the finite volume method of the center type of unstructured meshes, the interface flux is calculated by using the Godunov scheme, and the piecewise linear approximation MUSCL scheme is applied to the reconstruction of variables, and a two-dimensional hydrodynamic model with second-order accuracy in space and time is established. In order to improve the stability and computational efficiency of the two-dimensional model, the implicit two-step algorithm is introduced into the hydrodynamics to make the model more efficient and stable in the treatment of urban floods. A series of examples are used to test and verify the ability of the two-dimensional hydrodynamic model to deal with constant flow, discontinuous flow, moving boundary and actual terrain. It is proved that the model has good precision and sword speed. It can deal with dry and wet boundary problems effectively, can meet the requirements of harmony, can deal with complex water flow, urban buildings and actual terrain, and the algorithm has good robustness. The stability and efficiency of the model are greatly improved than that of the explicit scheme. (3) A two dimensional coupled urban flood model is established. An empirical formula and a mutual boundary condition are used to establish the surface lateral connection and forward connection of the one-dimensional model, and a new method to calculate the vertical flow exchange is proposed. On the basis of this, a numerical model of urban flood and waterlogging coupled with surface and underground is established. Two horizontal connection examples and one ideal vertical connection example are used to test the coupled model. The results show that the model has good accuracy and meets the requirement of water conservation. By applying the model to the risk analysis of dam-break flood of Minzhi reservoir in Shenzhen urban area and the calculation of rainstorm flood in Xinhepu community of Guangzhou, the reasonable results are obtained. It is proved that the one-dimensional coupled model established in this paper has the ability to deal with the actual terrain and practical problems, and can be applied to the numerical simulation of urban flood.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TV87;TU998.4

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