Research On 1D/3D Dual Coupled Of Precise Urban Rainstorm Flood Model

In recent years,the urban rainstorm flood disaster in China has become increasingly serious.it affects the safety of human life and property,and has become one of the major problems of urban development.It is of great significance to construct the urban rainstorm flood model for urban flood warning and forecast,and the flood control and disaster mitigation.This paper study the method of obtaining high-precision data,the numerical method for the complex flow pattern of the drainage pipe network,the runoff calculation method for refined urban sueface,coupled calculation method of ground and underground layers,and three-dimensional simulation of surface flood running.The main research results are as follows:(1)In the second chapter,in order to obtain high precision basic data of urban underlying surface,a Markov random field clustering algorithm based on multi-core fuzzy C-means(MKFCM-MRF)is proposed.This clustering algorithm is used to extract urban underlying surface features from high-precision UAV images.The clustering results show that MKFCM-MRF algorithm not only reduces noise,but also retains edge information,which improves the accuracy of underlying surface recognition.(2)The third chapter is to construct a fine urban storm flood model,the calculation method of surface runoff generation and confluence and the calculation method of coupling mode above ground and underground are studied in this paper.Firstly,a method for calculating the surface runoff on the basis of different coverage type grids is proposed;Secondly,a surface confluence calculation method considering the water exchange between adjacent sub-catchment areas is proposed;Finally,when calculating the inflow and overflow of rainwater by dual coupling of ground and underground,the coupling method of rainwater grate and rainwater well is proposed.Based on the above calculation method,a refined urban storm flood model is constructed.Taking a research area as an example,the model is used to simulate the short-term strong rainfall.The results show that the refined urban storm flood model has high calculation accuracy.(3)In the fourth chapter,In order to solve the problem of well-posedness of Priessmann four-point implicit difference scheme in jet flow and cross-critical flow,the convective acceleration term in momentum equation is splited in this paper.By verifying the analytical solution of open channel critical flow and open full flow test data,it is concluded that term αu/αx plays a decisive role in numerical simulation,while the influence of term αQ/αx on numerical simulation results can be ignored.(4)In the fourth chapter,in order to solve the problem of sudden change in the cross section of Rain Water pipeline caused by Rain Water well under the condition of insufficient flow,this paper analyses momentum theory and energy theory of sudden change control volume,and draw the conclusion that when the flow flows into Rain Water well,it has the influence of backwater,which makes the upstream water level rise,while when the flow flows out of the Rain Water well,the blocking phenomenon occurs and the upstream water level rises higher,and is consistent with the hydraulic test results.Through hydraulic test,it is also concluded that the average energy loss into Rain Water well is 0.106,and the average energy loss out of Rain Water well is 0.075.(5)The fifth chapter is to provide intuitive and effective display for flood control decision makers.This paper provides a three-dimensional urban flood running simulation model,by using smooth particle dynamics based on Meshless method,under the influence of built-up sets The tilt model is constructed with high precision data acquired by UAV.The grid-free urban flood routing model is further optimized.The three-dimensional real scene of urban storm flood routing is reproduced.The method can provide a reliable technical support for urban storm flood monitoring,and flood control and mitigation.