Flocculation kinetics-based cohesive sediment movement numerical simulation method

Abstract

The invention provides a flocculation kinetics-based cohesive sediment movement numerical simulation method. The method comprises the steps of (1) according to a river bed topography, generating un-structured triangular grids, comprising a main river channel and a beach part; (2) according to a water flow control equation, calculating hydraulic elements of the grids, and giving out upstream and downstream boundary conditions and river channel roughness in the calculation process; (3) calculating out change situations of particle size distribution and sediment settling velocity of cohesive sediment after flocculation; (4) obtaining sediment concentration and river bed erosion and deposition change situations of the corresponding grids; and (5) repeating the steps (2) to (4) until calculation of the whole time period is finished, simulating the whole movement process of the cohesive sediment, and giving out river channel sediment field distribution and river bed erosion and deposition change. The method simulatively calculates particle size distribution change of the cohesive sediment and sediment distribution fields under different hydrodynamic conditions, solves the problem of ignoring or simplification of flocculation influence in cohesive sediment transport simulation, and provides an important technical means for accurate simulation of cohesive sediment movement.

Description

technical field [0001] The invention relates to a numerical simulation method of viscous sediment movement based on flocculation dynamics, and belongs to the technical field of numerical simulation of sediment movement. Background technique [0002] Cohesive sediment widely present in suspension in natural water bodies will flocculate under the action of metal cations, water flow, organic matter, etc. Therefore, the research on the movement and transport characteristics of cohesive sediment has attracted much attention in recent years. [0003] However, due to the complex flocculation process of cohesive sediment and numerous influencing factors, the existing sediment movement models often ignore or only simplify the treatment by changing the sinking velocity to reflect the influence of flocculation. This processing method affects the model to a certain extent. The accuracy of the calculation limits the application of the model. [0004] Therefore, in order to more accurat...

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Problems solved by technology

[0005] On the basis of considering the flocculation characteristics of cohesive sediment, the present invention constructs a mathematical model of cohesive sediment movement, simulates and calculates the variation of cohesive sediment particle size distribution and the sediment distribution field under different hydrodynamic conditions, and solves the problem of cohesive sediment transportation. The problem of ignoring or simplifying the effect of flocculation in the migration simulation provides an important technical means for the accurate simulation of cohesive sediment movement

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