Direct numerical simulation of shallow flows over a rough bottom boundary: On the interaction between the deformable free-surface and the roughness-generated turbulence

粗糙底部边界上浅流的直接数值模拟：可变形自由表面与粗糙度产生的湍流之间的相互作用

• 批准号: 402125106
• 负责人: Dr.-Ing. Aman Ghebremichael Kidanemariam
• 金额: --
• 依托单位: Department of Mechanical Engineering
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/402125106?language=en
• 关键词: Direct; numerical; simulation; shallow; flows

Free-surface shallow flows are ubiquitous in nature. They are found in lowland alluvial rivers, estuaries, coastal areas and in man-made canals. The air-water interface in such flows is commonly observed to undergo a continuous spatio-temporal evolution featuring waves at a wide range of scales. Fundamental understanding of the mechanisms behind the free-surface dynamics is crucial from an environmental and engineering point of view as it greatly influences a number of relevant processes such as sediment and solute transport, interfacial mass and heat transfer and pollution dispersion. The rich dynamics of the free-surface is a consequence of a complex interplay between stabilizing and destabilizing factors such as gravity, the chaotic turbulent motion of the flow beneath and the evolving sediment bed. The proposed project aims to numerically investigate the physical mechanisms behind the often observed free-surface phenomena in turbulent shallow flows. To this end, a dedicated tool which utilizes state-of-the-art computational resources to simulate large-scale free-surface flows will be developed. Subsequently, the tool will be deployed to generate high-fidelity numerical data which resolves all the relevant scales of the problem. Rigorous analysis of the generated data will then follow to address the aforementioned coupled-interaction among the free-surface, the turbulent flow and the bottom rough bed. The results obtained in this project will fill existing knowledge gaps concerning the free-surface dynamics in environmentally-relevant shallow flows. It is anticipated that the results will serve as an important input in improving predictive models of the intrinsic processes in such flow configuration.

自由地面浅流本质上是普遍存在的。它们在低地冲积河流，河口，沿海地区和人造运河中发现。通常观察到这种流中的空气水界面会经历连续的时空演化，并在各种尺度上具有波浪。从环境和工程的角度来看，对自由地面动力学背后机制的基本理解至关重要，因为它极大地影响了许多相关过程，例如沉积物和溶质运输，界面质量，界面质量以及传热和污染分散体。自由表面的丰富动力学是稳定和不稳定因素（例如重力，下方流动的混乱湍流和不断发展的沉积物床）之间复杂相互作用的结果。拟议的项目旨在通过数值研究湍流浅水中经常观察到的自由表面现象背后的物理机制。为此，将开发一个专门的工具，该工具将开发出最先进的计算资源来模拟大规模的自由表面流。随后，将部署该工具以生成高保真数值数据，以解决问题的所有相关量表。然后，对生成数据的严格分析将遵循，以解决自由表面，湍流和底部粗糙床之间上述耦合的相互作用。该项目中获得的结果将填补有关环境与环境相关的浅水流中自由表面动态的现有知识空白。预计结果将是改善这种流程配置中内在过程的预测模型的重要输入。