Analysis And Study On Mathematical Model Available For The River Regulation Works On Fuyuan Reach Of Heilongjiang Main River

The task of the study is to research model test available for some key rivers with complicated river regimes and large land areas involved, conforming to the instructions given by Prime Minister Zhu Rongji after hearing the reports on Heilongjiang provincial border rivers protection projects during his inspection in Heilongjiang Province in July 2002, the general assignments made by the State Council on early-stage tasks of controlling the border rivers with severe territorial soil losses, and the examination views given by the Ministry of Water Resources about the Proposal on the Near-term Key Protection Works on Border Rivers with Severe Territorial Soil Losses in Heilongjiang Province, in order to provide credible basis for engineering design. The findings of the study, which were obtained through analogue calculation and analysis based on sediment mathematical models available for Fuyuan reach of Heilongjiang Main River, will provide scientific basis for the design and implementation of the regulation and protection works for the border rivers with severe territorial soil losses.The studies on modern sediment mathematical models began later than those on the models of other subjects for about ten to twenty years. At present, through more than thirty years of efforts made by hydrological specialists, both the one-dimensional model and the two-dimensional model had been applied in the cases of river bed deformation near hydraulic structure or river work, river bed deformation caused by shaping sediment alluvium dissipation, growth and movement in natural rivers, main branch's development and variation in a branching river, cross flood plain movement downstream, river bend scour and silting, shallow shoal evolution, river discharge and flood forecast, and flood routing in retarding basin etc. In fact the movements of flow and sediment always vary along with three space directions including route, depth and width, which belong to three-dimensional questions. Three-dimensional model is seldom applied now due to its complication and requirements on calculation means.Aiming at the 28km long river regulation and protection works on Fuyuan reach where the river evolutions are complicated and the dimensions of control works are difficult to calculate, this dissertation is to study three-dimensional numerical analogue not only under natural conditions but also under ten regulation schemes, using the river sediment quasi-two-dimensional model associated with the river sediment plane two-dimensional model and the river three-dimensional model. At the same time, the method combing the VOF model of water and gas currents and the K- ?model is also introduced into the calculation and analogue. The SIMPLEC method, which was improved based on the SIMPLE method, is adopted to find the numerical value answers, and the non-structured mixed grid is adopted for grid partition to enhance its self-adaptability to complicated border conditions. Through checking computations, it was shown that the analogue accuracy of the model was quite high, which can provide important basis for scientific decision-making on engineering measures. Through analogue calculation and analysis of many regulation schemes, it was shown that combining the diversion weir works with the bed fixing works at the south branch is reasonable and feasible in the implementation of Loushuikouzi river regulation works. In addition, it is suggested that the bed fixing works at the south branch should adopt the improved compound section scheme. The improved scheme can ensure the south branch to be open to navigation and the flow here not to be broken in low water seasons, and it will have active effect on protecting the south branch and Fuyuan Town.This study is an attempt of applying three-dimensional mathematical model in analogue calculation and analysis of flow, sediment and riverbed movements in a long river reach. It is very important for the future thorough research, and has great significance for promoting the application of the three-dimensional model to reso...