湖泊流场数学模型及水动力特性研究

发布时间：2018-06-22 18:31

本文选题：自适应网格 + 浅水方程　；参考：《华中科技大学》2014年博士论文

【摘要】：湖泊是地球水循环系统的重要组成部分,在人类活动的影响下,城市湖泊的水文过程以及生态系统结构同自然状态相比均发生了深刻的变化。研究自然环境与人类活动等多重影响因素驱动下的湖泊水循环系统演变过程,分析不同水-陆、水-气、湖泊底质等约束条件下湖泊流场的分布形态,探索湖泊水体的时空运动规律,进而为湖泊水环境治理、湖泊水生态调控与改善、大型湖泊水网连通工程优化调度提供科学依据,共同组成了一项重要且迫切的研究命题,建立湖泊流场水动力数学模型、准确高效地模拟湖泊水体运动过程正是完成这一研究命题的重要途径。然而,我国在湖泊水动力水质高效模拟方面的研究还不够系统和深入,难以为湖泊水质改善、水生态修复提供有效的决策依据,无法为我国日益严重的城市水环境劣化问题提供有效的技术支撑。因此,亟需在湖泊流场水动力数值模拟方面开展深入研究,建立一套高效稳定的湖泊流场数值计算模型,揭示复杂边界条件下大型湖泊群的水动力学特性,为水资源管理机构制定水生态修复调度决策方案提供科学依据。本文以连通湖泊群为研究对象,基于浅水动力学理论建立了适用于不规则水陆约束条件和复杂地形条件下的湖泊水体高性能二维数学模型,分析了不同自然环境因素以及不同人工调度引水策略下的湖泊水动力学特性,并以武汉大东湖湖泊群为实例研究区域分析了各湖泊内的水体运动特征以及主要驱动力,探讨了提高滞水区水体更新速率的有效方法,相关成果应用于水利部公益性行业科研专项经费项目“大东湖水网调度关键技术研究及应用”中。本文主要研究工作及创新点包括： (1)建立了一套结构灵活的自适应网格模型,提出了网格自适应变化准则,依据局部水流运动特征,动态调整计算网格密度,实现了计算精度与计算效率的平衡,有效解决了大型湖泊计算耗时与高精度流场数值分析的矛盾。 (2)基于结构网格模型提出了一种针对二维浅水方程的简单和谐数值格式。针对二维浅水方程求解过程中传统的底坡项近似方法及通量计算格式在处理干湿界面时存在虚假流动的问题,提出了一种便捷的和谐格式,通过理论推导与测试算例,验证了数值格式的静水和谐性,能够稳定高效地模拟包含动态干湿界面的水体运动过程。 (3)运用一系列国内外广泛使用的经典理论算例与室内观测试验对模型进行了系统地测试检验。测试结果表明,数值模型具有良好的静水和谐性、水量守恒性、流态突变高分辨率捕捉、以及复杂边界有效拟合等特点。 (4)分析了湖底形态、湖岸边界形状、表面风应力、湖泊初始水位、湖心岛等因素对湖泊稳定流场的建立时间、水深分布、流速分布等方面的影响。 (5)基于水动力学数学模型构建了大东湖湖流计算数值模型,对大东湖水域内的水体运动进行了模拟,分析了主要湖泊与子湖内的水体运动特征以及不同环境驱动力对湖泊流场的贡献；结合各湖滞水区流场的主要动力,提出了可提高湖泊滞水区内水体流速的有效调度策略。
[Abstract]:Lake is an important part of the earth's water circulation system. Under the influence of human activity, the hydrological process and the ecosystem structure of the urban lakes have undergone profound changes compared with the natural state. The study of the evolution process of the lake poke water cycle system driven by the multiple factors such as natural environment and human activities, analyses the different water land. The distribution pattern of lake flow field under the constraints of water gas and lake bottom, explore the law of space-time movement of lake water, and then provide a scientific basis for lake water environment control, lake water ecological regulation and improvement, the optimization and scheduling of large lake water network connected engineering, together with an important and urgent research proposition, and the establishment of lake flow. The mathematical model of field hydrodynamic force is an important way to complete the study of lake water movement accurately and efficiently. However, the research on high efficiency simulation of water dynamic water quality in China is not systematic and in-depth. It is difficult to provide effective decision-making basis for the improvement of lake water quality and water ecological restoration, which can not be used for our country. Serious urban water environmental degradation provides effective technical support. Therefore, it is urgent to study the hydrodynamic numerical simulation of lake flow field, establish a set of efficient and stable numerical model of lake flow field, reveal the hydrodynamic characteristics of large lakes under complex boundary conditions, and formulate water ecology for water resource management institutions. It provides a scientific basis for the repair scheduling decision.
In this paper, based on the lake group as the research object, based on the theory of shallow water dynamics, a two-dimensional mathematical model for the high performance of lake water under the conditions of irregular water and land constraints and complex terrain is established, and the hydrodynamic characteristics of lakes under different natural environmental factors and different artificial dispatching strategies are analyzed, and the great east of Wuhan is given. The lake and lake group have analyzed the characteristics of water movement and the main driving force in the lakes for the case study. The effective methods to improve the water renewal rate in the stagnant water area are discussed. The related achievements are applied to the special fund project of the public welfare industry of the Ministry of water resources, "the research and application of the key technology of the dispatching of the water network in Dadong Lake". The work and innovation include:
(1) a set of adaptive mesh model with flexible structure is set up, and the adaptive change criterion of grid is put forward. According to the characteristics of local flow movement, the calculation grid density is dynamically adjusted. The balance of calculation precision and calculation efficiency is realized, and the contradiction between the time-consuming of large lakes calculation and the numerical analysis of high precision flow field is effectively solved.
(2) a simple and harmonious numerical scheme for two-dimensional shallow water equation is proposed based on the structural grid model. In the process of solving two-dimensional shallow water equation, the traditional bottom slope approximation method and the flux calculation format have the false flow problem in the dry and wet interface. A convenient and harmonious format is proposed, and the theoretical derivation and measurement are carried out. A trial example verifies the hydrostatic compatibility of the numerical scheme, which can simulate the movement process of water body containing dynamic dry wet interface efficiently and stably.
(3) the model is tested and tested systematically with a series of classical theoretical examples and indoor observation tests, which are widely used both at home and abroad. The results show that the numerical model has good static water harmony, water conservation, high resolution capture of flow mutation, and the effective fitting of complex boundary.
(4) the influence of the lake bottom shape, the shape of the lakeshore boundary, the surface wind stress, the initial water level of the lake, the lake Heart Island and other factors on the establishment time of the stable flow field, the distribution of water depth, the distribution of the flow velocity and so on.
(5) based on the hydrodynamic mathematical model, the numerical model of the great East Lake lake flow calculation is constructed, and the water movement in the great East Lake waters is simulated. The characteristics of the water movement in the main lakes and the lakes and the contribution of different environmental driving forces to the flow field of the Lake are analyzed. Effective scheduling strategy for water velocity in Lake stagnant area.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TV131.2;P343.3

【参考文献】