Flow confluence calculation method in complex underlying surface condition of city

Abstract

The invention discloses a flow confluence calculation method in a complex underlying surface condition of a city. The method comprises following steps of: step 1, constructing a kinematic wave equation describing an overland flow motion and setting initial conditions and boundary conditions; step 2, constructing an evolution equation on the basis of a discrete velocity model; step 3, processing and calculating multi-scale problems of the Lattice Boltzmann method; step 4, determining an equilibrium state distribution function; step 5, processing the initial conditions and the boundary conditions; and step 6, solving an overland flow motion equation through the improved Lattice Boltzmann method. Compared with the prior art, the flow confluence calculation method can be applied for solving the overland flow motion equation, and by means of the processing method of the multi-scale problems, solving precision of the overland flow motion equation is effectively improved, and problems of increasing complexity of the underlying surface terrains and covering features of a drainage basin in a background of acceleration of urbanization processes are solved.

Description

technical field [0001] The invention relates to the field of computational fluid dynamics, in particular to a confluence calculation method under complex underlying surface conditions in cities. Background technique [0002] Slope water flow is an important part of the research on runoff generation and confluence, and plays a pivotal role in the field of hydrology and applied research. At the same time, slope water flow is the main driving force of soil water erosion process. Therefore, accurate simulation of slope water flow movement process is very important for revealing slope It is of great significance to study the law of surface water flow, clarify the mechanism of slope erosion, and build a simulation of the physical process of soil erosion. [0003] Slope flow movement belongs to the category of fluid movement. At present, the description of fluid motion can be carried out from three observation scales: macroscopic, mesoscopic, and microscopic. The macroscopic cont...

AI Technical Summary

Problems solved by technology

However, it is undeniable that there are still challenges in describing fluid motion at the macro level: ① For some complex situations, such as turbulent flow, porous medium flow, and cross-scale flow, macroscopic models have great limitations due to the complexity of flow mechanisms or boundary conditions

② For strongly nonlinear differential equations, numerical stability is a big problem

Among them, the proposal of the Lattice BGK model transforms the complex collision operation into a simple relaxation process. The matrix is ​​determined by the relaxation time, which greatly simplifies the calculation and greatly improves the calculation efficiency of the Lattice Boltzmann method, which has aroused widespread attention at home and abroad. attention, but so far there are few reports on the application of the Lattice Boltzmann method to slope water movement

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