Second-order discontinuous Galerkin flood model: Comparison with industry-standard finite volume models
Second-order discontinuous Galerkin flood model: Comparison with industry-standard finite volume models
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DOI：
10.1016/j.jhydrol.2020.125924
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发表时间：
2020-10
影响因子：
6.4
通讯作者：
Janice Lynn Ayog;G. Kesserwani;James Shaw;M. Sharifian;D. Baù
中科院分区：
文献类型：
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作者：
Janice Lynn Ayog;G. Kesserwani;James Shaw;M. Sharifian;D. Baù
二维浅水方程的有限体积(FV)数值解算器是工业标准洪水模型的核心。二阶不连续Galerkin(DG2)方法虽然是改进当前基于FV的洪水模型的一种可行方法，但仍处于研究阶段，很少用于支持洪水模拟应用程序。本文系统地研究和比较了稳健DG2洪水模型和基于FV的工业洪水模型的预报特性。为了确定适合洪水淹没模拟的最简单和最有效的DG2配置，考虑了两种变量--有和没有局部坡度限制。比较了DG2变种与一阶FV(FV1)和二阶FV(FV2)的数值守恒性质。然后，DG2变种在英国环境署推荐的五种现实洪水场景中进行测试，以验证2D洪水模型的能力，同时将它们的性能与四种基于FV的商业模型(即TUFLOW-FV1、TUFLOW-FV2、TUFLOW-HPC和Infoworks ICM)进行比较。结果表明，无局部限制的DG2变种(DG2-NL)能够模拟广泛的洪水模拟应用中的无激波洪水流动。DG2-NL以两倍粗的空间分辨率显示了与商业模型输出更接近的预测，并且运行速度可以快一倍，通过远程模拟产生更多信息丰富的过程线，即使在采样距离洪水源较远的情况下也是如此。
Finite volume (FV) numerical solvers of the two-dimensional shallow water equations are core to industry-standard flood models. The second-order Discontinuous Galerkin (DG2) alternative, although a viable way forward to improve current FV-based flood models, is yet under-studied and rarely used to support flood modelling applications. This paper systematically explores and compares the predictive properties of a robust DG2 flood model to those of prominent FV-based industrial flood models. To identify the simplest and most efficient DG2 configuration suitable for flood inundation modelling, two variants – with and without local slope limiting – are considered. The numerical conservation properties of the DG2 variants are compared to those of a first-order FV (FV1) and a second-order FV (FV2) counterparts. The DG2 variants are then tested over five realistic flooding scenarios, recommended by the UK Environment Agency to validate 2D flood model capabilities, while comparing their performance against that of four FV-based commercial models (i.e. TUFLOW-FV1, TUFLOW-FV2, TUFLOW-HPC and Infoworks ICM). Results reveal that the DG2 variant without local limiting (DG2-NL) is capable to simulate shockless flood flows featured in a wide range of flood modelling applications. The DG2-NL shows closer predictions to commercial model outputs at twice-coarser spatial resolution, and can run twice faster to produce more informative hydrograph with small-scale transients over long-range simulations, even when the sampling is far away from the flooding source.