A method and system for simulating flood scour evolution of steep riverbeds

Abstract

Embodiments of the present invention provide a simulation method and system for evolution of flood scoured scarp riverbed. The method comprises: processing a water flow vector equation as shown in the description by using a spatial discrete sub-item mixed method; using Godunov-Riemann format to solve the water flow vector equation as shown in the description processed by the spatial discrete sub-item mixed method, to obtain a solution of a variable U; discretely solving a water gradient as shown in the description of a source term S by using a differential method, and obtaining a discretized water gradient term for a water gradient, performing spatial numerical reconstruction of a discontinuous point on the discretized water gradient term after, further solving a water level critical value at a right interface and a water level critical value at a left interface; according to a bed load sediment transport equation as shown in the description, solving a single-wide transport rate qs, discretizing a riverbed deformation equation as shown in the description by using a finite differential method of a back difference format; and then according to the single-wide transport rate qs and the corrected variable U, solving a riverbed surface elevation zb. According to the method provided in the present invention, high precision and high efficiency numerical simulation of the evolution of steepfall riverbed under the flood can be achieved, and riverbed flood of seasonal dry and wet and riverbed erosion and deposition can be properly solved.

Description

technical field [0001] The invention relates to the field of simulation, in particular to a method and system for simulating the scour evolution of steep riverbeds. Background technique [0002] Strong crustal movement or human factors such as river sand mining can lead to local subsidence or uplift of the river bed, forming scarps with large water drop. The steep slopes lead to strong changes in the flow regime of the current, and in turn, the strong movement of the sediment by the currents leads to the rapid evolution of the riverbed in the steep slopes. During the flood period, this evolution is more severe, which directly or indirectly leads to the destruction of bridges and other cross-river projects, and brings safety hazards to production and life. The dams formed by the Wenchuan earthquake in my country in 2008 and the large-scale sand mining pits in the riverbed that caused the collapse of a railway bridge in 2002 are all steep riverbeds with potential disasters. ...

AI Technical Summary

Problems solved by technology

[0003] The current status of research on the evolution of steep riverbeds in the prior art mainly has the following problems: 1) In the current safety regulations for crossing river projects, the safety distance between the project and the steep riverbed is only stipulated according to the level of the project scale, and the river course is not fully considered. 2) There are many qualitative analyzes on the erosion and deposition evolution of steep riverbeds, but there are few quantitative and high-precision numerical simulations and predictions based on theories of water, sand movement and riverbed deformation. method; 3) The water flow near the steep slope is a large gradient transcritical flow, and there is a discontinuity. The traditional numerical methods for calculating water flow—difference method and finite volume method are prone to numerical oscillation at the discontinuity point of the steep slope. The governing equation requires the calculation variables to be continuous at all points in space, but the flow state near the steep slope does not meet this requirement; 4) It is difficult for any numerical format to meet the following requirements of numerical calculation at the same time: continuous everywhere, high-order accuracy in time and space, and high calculation efficiency

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