Construction And Analysis Of Three-dimensional Hydrodynamic Mathematical Model Of Inner Mongolia Reach Of The Yellow River

Natural water must have three-dimensional motion.In order to simulate natural water more accurately and comprehensively,a three-dimensional hydrodynamic mathematical model must be established.With the maturity of numerical simulation technology and the indepth study of three-dimensional water flow,it has become a trend to study the hydrodynamic situation of the river basin through three-dimensional hydrodynamic model.The river remediation of the Inner Mongolia reach of the Yellow River provides a theoretical basis for further research,such as sediment transport and riverbed deformation research.Based on the previous work,this paper established a three-dimensional hydrodynamic mathematical model based on the open source program ELCIRC.The principle and method of the three-dimensional hydrodynamic model are expounded in detail,and the treatment of key problems in the simulation process is discussed.A series of simplifications and approximations are made to the complete three-dimensional NS equation according to the actual situation.Considering the small vertical flow velocity,the assumption of static pressure is adopted.The three-dimensional water flow control equation below,the free water surface treatment adopts the water level function method,the turbulent closed model adopts the GLS model,the horizontal grid can choose the structured grid or the unstructured grid,the vertical grid adopts the Sigma coordinate,and the variable arrangement is also carried out accordingly,description to ensure the feasibility of the model for practical application.This paper expounds the optimized and improved structure of the original model in detail,including the model input form and input file,the output form and output file,the solution process of the model,and various details that need to be paid attention to in the model.Then the classical three-dimensional dam break physical test and the curve model physical test are simulated and calculated,and the simulated results of water level and velocity field distribution are compared and verified with the measured values.The results show that the three-dimensional hydrodynamic mathematical model prepared in this paper can simulate the actual The water flow moves and has good stability.In this paper,the verified 3D hydrodynamic model is applied to a typical reach of the Inner Mongolia of the Yellow River,and xiliugou Entrance to the Yellow River is selected as the research object according to the hydrological background data.Based on the Yellow River water conservancy science research institute of terrain data and hydrological data,first of all,the region's three dimensional flow model is set up and strength of two groups representing different flooding condition for parameter calibration,after adjusting for the roughness continuously optimized and calculated value tallies with the measured values of contrast verification results,show that the established model can well simulate the river water flow movement.Secondly,this model is used to analyze and compare the velocity field and vertical velocity distribution of the monitoring point and its surroundings in the Inner Mongolia reach of the Yellow River.Then the two conditions of import and export flow,flow forming region and intersection zone flow field were analyzed,the intersection of three dimensional flow structure were analyzed,the results show that two kinds of working condition will cause certain floodplain,and the second condition would have a wide range in the intersection area,vertical intersection water upwelling and down stream.The model established in this paper can provide a certain theoretical basis for flood prediction and has very important significance for practical engineering application.