Experimental calibration and validation of sewer/surface flow exchange equations in steady and unsteady flow conditions
Experimental calibration and validation of sewer/surface flow exchange equations in steady and unsteady flow conditions
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DOI：
10.1016/j.jhydrol.2017.06.024
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发表时间：
2017-09-01
影响因子：
6.4
通讯作者：
Shucksmith, James
中科院分区：
文献类型：
--
作者：
Rubinato, Matteo;Martins, Ricardo;Shucksmith, James
污水管流和漫滩流之间的联系被认为是引起二维（2D）城市洪水模型的不确定性的重要来源。这种不确定性通常归因于使用经验水力公式（一维（1D）堰和孔口稳流方程）来实现连接界面处的数据连接，这需要确定流量系数。由于缺乏高分辨率的本地化数据，这种类型的流量，目前的理解和量化的适当范围，这些流量系数是有点缺乏。为了填补这一空白，这项工作提出了从仪器化的物理模型，旨在研究管网流量和河漫滩流量之间的相互作用所获得的结果。在稳定和不稳定的流动状态下，对交换区的下水道到地面和地面到下水道的流动条件进行了实验分析。稳态测量流量首先分析考虑从下水道流和河漫滩流的能量头之间的关系，这些结果表明，现有的堰和孔口公式是有效的，用于描述本物理模型的流量交换，并产生新的校准流量系数为每个流量条件。所测得的交换流量也集成（作为源项）内的二维数值洪水模型（有限体积求解器的二维浅水方程（SWE）），这是重现所观察到的系数。然后，使用该校准的数值模型来模拟在实验设施内再现的一系列非定常流测试。结果表明，数值模型高估了平均超载流量值。这表明在非稳定条件下会发生额外的水头损失，目前在稳定流条件下校准的洪水模型中未考虑到这一点。(C)2017作者（S）由爱思唯尔公司出版
The linkage between sewer pipe flow and floodplain flow is recognised to induce an important source of uncertainty within two-dimensional (2D) urban flood models. This uncertainty is often attributed to the use of empirical hydraulic formulae (the one-dimensional (1D) weir and orifice steady flow equations) to achieve data-connectivity at the linking interface, which require the determination of discharge coefficients. Because of the paucity of high resolution localised data for this type of flows, the current understanding and quantification of a suitable range for those discharge coefficients is somewhat lacking. To fulfil this gap, this work presents the results acquired from an instrumented physical model designed to study the interaction between a pipe network flow and a floodplain flow. The full range of sewer-to-surface and surface-to-sewer flow conditions at the exchange zone are experimentally analysed in both steady and unsteady flow regimes. Steady state measured discharges are first analysed considering the relationship between the energy heads from the sewer flow and the floodplain flow; these results show that existing weir and orifice formulae are valid for describing the flow exchange for the present physical model, and yield new calibrated discharge coefficients for each of the flow conditions. The measured exchange discharges are also integrated (as a source term) within a 2D numerical flood model (a finite volume solver to the 2D Shallow Water Equations (SWE)), which is shown to reproduce the observed coefficients. This calibrated numerical model is then used to simulate a series of unsteady flow tests reproduced within the experimental facility. Results show that the numerical model overestimated the values of mean surcharge flow rate. This suggests the occurrence of additional head losses in unsteady conditions which are not currently accounted for within flood models calibrated in steady flow conditions. (C) 2017 The Author(s). Published by Elsevier B.V.