A Novel Riemann Solver for Modelling Partial Barriers to Flow within 2-D Hydrodynamic Models

洪水模型是洪水风险管理实践的重要组成部分，因为洪水模型产生的结果被用来为未来的投资提供信息。因此，准确的洪水模型对于有效的洪水风险管理至关重要。在集水区内，桥梁结构等线性地物可以作为水流的部分障碍，显著影响洪水的行为。然而，尽管准确地模拟洪水流动对于有效的洪水风险管理具有确定的重要性，但目前还没有一个洪水模型能够明确地模拟洪水流动与部分水流障碍之间的相互作用。在当代行业实践中，这些特征通常使用粗略的近似、基于经验的方法或完全省略这些特征来建模。因此，提出了一种新的解算器的开发，该解算器能够显式地模拟洪水流动与部分水流障碍之间的相互作用。这种解决方案的开发将保证更有效的洪水风险管理，包括在桥梁结构分析、基础设施弹性建模以及海啸和大坝决口情景等方面的进展。新型求解器的开发将首先在适当的编程语言中开发基准模型，使用行业标准洪水模型使用的现有求解器。随后，将在最先进的多功能水槽中进行实验，以研究物理行为并教育新型解算器的开发。求解器的开发将以某种迭代的方式进行：通过比较数值模型的预测和实验过程中记录的观察现象，可以理解观察到的差异的物理逻辑原因，从而可以识别和实施对求解器的必要更改。一旦获得了足够的精度并优化了代码，将使用新型求解器、基准模型和开放源码的3D计算流体力学分析软件来复制在多功能水槽内进行的实验场景，并对结果进行比较。通过与实验结果的比较，可以验证各个模型的预测能力，通过不同模型之间的比较，可以确定新型求解器的相对精度和数值。因此，这项研究的目标可以概括为：1.利用现有的解决方案开发一个基准模型。在最先进的多功能滑梯内进行实验。开发并实现一种新的解算器，能够显式地模拟洪水流动和部分水流障碍之间的相互作用。用实验数据验证了该解算器的预测能力。将新的求解器产生的结果与其他商业上可用的解决方案进行比较。

Flood modelling is a vital component of flood risk management practice, as the results produced by flood models are used to inform future investment. Accurate flood modelling is therefore vital to effective flood risk management. Within catchments, linear features, such as bridge structures, can act as partial barriers to flow, significantly influencing the behaviour of flood flows. However, despite the established importance of accurately modelling flood flows for effective flood risk management, no flood model currently has the capacity to explicitly model the interaction between flood flows and partial barriers to flow. Within contemporary industry practice such features are often modelled using coarse approximations, empirically based methods or by omitting such features entirely. The development of a novel solver, capable of explicitly modelling the interaction between flood flows and partial barriers to flow is therefore proposed. Development of such a solver would promise more effective flood risk management including advances in the structural analysis of bridges, infrastructure resilience modelling and tsunami and dam break scenarios, among others. Development of the novel solver is to be achieved by first developing a benchmark model within a suitable programming language, using existing solvers utilised by industry standard flood models. Following this, experiments within a state-of-the-art multipurpose flume are to be conducted to study the physical behaviour and educate the development of the novel solver. The development of the solver is to be conducted in a somewhat iterative manner: by comparing the predictions of the numerical model and the observed phenomena recorded during the experimentation process, an understanding of the physically logical reasons for the observed differences can be developed and consequently necessary changes to the solver can be identified and implemented. Once sufficient accuracy has been achieved and the code has been optimised, the experimental scenarios conducted within the multi-purpose flume are to be replicated using the novel solver, benchmark model and open-source 3D computational fluid dynamics analysis software and the results compared. Through comparison with the experimental results the predictive capacity of the respective models can be validated and via comparison between the different models the relative accuracy and value of the novel solver can be determined. The objectives for the study can therefore be summarised as:1. Develop a benchmark model using existing solvers.2. Conduct experiments within a state-of-the-art multipurpose flume.3. Develop and implement a novel solver capable of explicitly modelling the interaction between flood flows and partial barriers to flow.4. Validate the predictive capacity of the novel solver against experimental data.5. Compare the results produced by the novel solver to other commercially available solutions.