Coupling analysis method for one-dimensional mathematical model and two-dimensional mathematical model of river way outburst flood

Abstract

The invention provides a coupling analysis method for a one-dimensional mathematical model and two-dimensional mathematical model of river way outburst flood. After corresponding data is collected, adyke breach outflux inundated area and a river way section obviously influenced by dyke breach outflux are first dispersed by using a quadrilateral or triangular unstructured grid, and other river sections adopt one-dimensional cross-section data generalization. The one-dimensional model is solved by adopting a classical Presimann implicit format, the two-dimensional model is solved by adopting aGodunov format with a shock capturing ability. In order to avoid numerical oscillation, mass conservation and momentum conservation of the connection portion between the one-dimensional mathematical model and the two-dimensional mathematical model are ensured; according to the coupling analysis method for the one-dimensional mathematical model and two-dimensional mathematical model of river way outburst flood, provided connection portion is a transition region, one-dimensional model calculation and two-dimensional model calculation are both conducted in the transition region. After the dyke breach is started, the dyke breach outflux inundated area and a river way two-dimensional computing area automatically become an integrated two-dimensional computing area, and the calculation of dyke breach outflux process is completed by the two-dimensional model. The processing method can fully consider the hydrodynamic response process inside and outside the river way on the dyke breach, the numerical simulation precision of the dyke breach outflux process is improved, and the shortcoming in a traditional method is overcome that only a weir formula is adopted to calculate the dyke breach outflux process, so that the momentum exchange inside and outside the river way can not be considered.

Description

technical field [0001] The method relates to the field of water conservancy engineering, in particular to the field of flood control and disaster reduction, and is specifically a coupling analysis method for one-dimensional and two-dimensional mathematical models of river burst floods. Background technique [0002] Embankment is a water-retaining structure built along the banks of rivers, lakes, oceans or flood storage and detention areas, polders, and reservoir areas to prevent flood overflow or storm attack, and is an important part of the flood control engineering system. Historically, the records of embankment breaches in my country are astonishing. In recent years, with the continuous increase of the country's investment in water conservancy projects, the flood control standards and engineering quality of embankments on major rivers have been significantly improved, but dike breaches still occur from time to time. [0003] At present, there are two commonly used methods...

AI Technical Summary

Problems solved by technology

One is the hydrological method, which is based on the principle of water balance and combined with geographic information data, can give the final submerged range of the flood, but this method is generally used in relatively small and closed areas, and cannot provide detailed information. hydrodynamic submersion process

The other is the method of hydrodynamics. Due to the high efficiency of the one-dimensional model, relatively little terrain data is required, and at the same time, it can easily deal with some hydraulic structures. It is widely used in river flood simulation. Some water flows with obvious two-dimensional properties, such as surface flood evolution without a fixed path, have great limitations

The two-dimensional model has obvious advantages in dealing with complex water flow, with higher accuracy, but there are also disadvantages such as low computational efficiency

[0004] At present, the one-dimensional and two-dimensional coupled mathematical model technology of dike breaks has been developed relatively stably. Basically, the coupling position is set at the breach. There is a very prominent problem, that is, when a breach occurs, a very complicated hydrodynamic response process will appear in the channel near the breach. Looking at the breach along the vertical direction of the channel, the water level of the channel near the breach drops rapidly, and far away from the breach. The water level of the river on one side of the river drops slowly, especially when the river is wide, the water level on the other side of the breach will not even change very obviously. This phenomenon is purely due to the conditions such as energy conservation and water volume conservation at the channel breach set in the one-dimensional model. If it is assumed to solve the problem, it will homogenize the hydrodynamic change process in the channel near the breach, which will bring large numerical errors to the final calculation results. In addition, this coupling method often has numerical oscillation problems during the receding stage. In order to eliminate the numerical Oscillation will artificially adopt some numerical smoothing methods, which will also bring large errors to the calculation results

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