Study On The Evolution Mechanism Of The Lacustrine Delta Based On Numerical Simulation And Natural Modeling

Delta is the production of sediment deposition due to the effect of water resistance when the river enters the ocean,lake,etc.When the slope of lake basin is small and the delta is more affected by the river,shallow water delta will be formed.There are several typical shallow water deltas in China,which play an important role in balancing the ecology of great rivers and the healthy development of the lakes and rivers.The study can not only improve the evolution theories,but also provide effective guidance for river way planning,preventing disasters and predicting oil and gas resources.The numerical simulation method and the natural model method are used to analyze the river evolution and sediment accumulation process.The water sediment mathematical model researched by the sediment Laboratory of the river and coastal engineering of Tianjin University is used as a tool to analyze the sediment deposition and the rule of the flow field changing under different inflow conditions.In the River Dynamics Laboratory of Tianjin University,the formation and evolution of the delta are simulated by using the generalized flume.According to the evolution characteristics of the lacustrine delta,the evolution process under each condition is divided into six stages;Analysis the development pattern of the mouth bar;Study on the memory characteristics of flow path;The surface flow field is obtained by PTV,and the flow field characteristics are analyzed;The evolution experiment of lacustrine delta and its channel system are designed and completed,the phenomena and rules have been recorded and summarized.The phenomena occured during the formation and evolution process of different flow conditions are recorded;The characteristics of deposit growth in longitudinal,transverse,vertical directions and evolution rules of coastline outline are analyzed.