A flow-through treatment method for linear water-retaining structures under a numerical simulation framework

Abstract

The invention discloses a flow-through treatment method of a linear water-retaining structure under a two-dimensional non-structural flood numerical simulation framework. After obtaining the terrain and geomorphic data of the calculation area and the geometric feature data of the linear water-retaining structures, a quadrilateral unstructured grid is used to discretize the calculation area, and the center line of the linear water-retaining structures is used as the control line for grid division. After the meshing is completed, the grid cell edges representing linear water-retaining structures are defined as special edges, and the rest of the cell edges are defined as boundary edges and common edges. According to the ratio of the top width of the linear structure to its upstream water depth to judge the weir flow shape, the corresponding weir flow formula is used to calculate the single-width flow through the special edge, and the mass flux and momentum flux through the normal direction outside the special edge can be obtained. quantity. This processing method can take into account the mass exchange and momentum exchange process on both sides of the linear structure while taking into account the computational efficiency, which makes up for the shortcomings of the existing methods.

Description

technical field [0001] The invention belongs to the technical field of water conservancy engineering, and in particular relates to a flow-through treatment method of a linear water-retaining structure under a two-dimensional non-structural flood numerical simulation framework. Background technique [0002] The so-called linear water-retaining structures refer to structures such as expressway embankments, railway embankments, and water-retaining embankments that are often encountered in the calculation area. The tops of these structures are usually higher than the ground, and their spatial forms are linear. When a flood occurs, these structures will play an obvious role in blocking water, and when the water level on one side is greater than the elevation of the top, overflow will occur. [0003] In engineering practice, a two-dimensional shallow water model is usually used to simulate a large-scale flood flow process. In the calculation of two-dimensional flood numerical sim...

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Problems solved by technology

At present, there are two commonly used methods to deal with these linear structures under the framework of two-dimensional non-structural numerical simulation. One is to use a fine grid to separate the linear structures, which requires very fine terrain data to support, but when When performing large-scale flood analysis, on the one hand, the cost of obtaining such fine terrain is too high; on the other hand, although the numerical accuracy of this kind of processing is high, it will bring catastrophic calculation efficiency problems at the same time, so in practical applications The other is a very simplified treatment method, which uses the wide-crested weir flow formula to directly transfer the water flow through the top of the linear water-retaining structure to the downstream grid, and only considers the water exchange on both sides of the linear water-retaining structure. However, the exchange of water flow on both sides is ignored, and the different weir flow characteristics at the top of the linear water retaining structure are usually not distinguished, which will have a great impact on the actual calculation accuracy

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