A Calculation Method for Roughness of Two-dimensional River Flow Model

Abstract

The invention discloses a river plane two-dimension current model roughness calibration method comprising the following steps: 1, delimiting roughness zones according to river plane features, and initializing the roughness in each zone; selecting the present flow rate with to-be-calibrated roughness and the corresponding river reach outlet water level; using a river plane two-dimension current mathematics model to carry out water-power calculation; determining errors between a model calculated value and an actual measurement value of each monitoring point water level; determining whether the water level error is small enough or not; determining a water pass area according to the water depth, and using all monitoring point water level error interpolation to estimate the water level errors between all grid points in the water pass area; using a dichotomy to adjust the roughness of the grid points in the water pass area according to the water level errors of all grid points in the water pass area; further determining whether all to-be-calibrated flow rates have been calibrated or not; if yes, finishing roughness calibration, and storing the roughness calibration result. The method can reduce artificial interferences in an iteration trial process, thus solving the problems that an existing method is unclear in technical process, rigid in conditions, and hard to apply.

Description

Technical field [0001] The invention relates to the technical field of river dynamics research, in particular to a method for determining the roughness of a two-dimensional water flow model of a river channel. Background technique [0002] Roughness is an important parameter of a two-dimensional river flow mathematical model (hereinafter referred to as "two-dimensional flow model"). The two-dimensional flow model can be used to calculate the flow velocity, water level, and depth of natural rivers. The acquisition of these hydraulic elements can be Provide hydraulic conditions for solving water conservancy, ecological and environmental issues. The realization of the two-dimensional water flow model on the computer is called "the river plane two-dimensional water flow mathematical model software". The calculation process is essentially the process of solving discrete flat two-dimensional shallow water equations, except for the need to specify initial conditions and boundary conditi...

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Problems solved by technology

However, the above three types of methods have shortcomings such as unclear procedures, harsh conditions, and difficulty in application. At present, there is no empirical or theoretical formula that can directly calculate the roughness distribution of a plane two-dimensional bed surface, and because the previous iterative trial calculation process mainly relied on Manual intervention has no rules and is highly subjective. Even if the same model is used to deal with the same river section, the roughness ratio obtained by different personnel is also very different.

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