Numerical Study On Three-Dimensional Flow Structure Of Dig-in Basin In Inland River

Dig-in basin is a common type of port layout. It is more widely used in China’s provinces and cities which have developed inland shipping. But during the operation, there are silt sediment which mainly results from the circumfluence and the density current in the dig-in basin. Therefore, the in-depth study of three-dimensional flow structure is important to the research of silt sediment in the dig-in basin.On the basis of previous study, this paper simulate the 3-D flow in the dig-in basin and summarize the general rules by numerical experiments and data analysis under the different conditions. Then we explore simple anti- silt sediment measures aim to the circumfluence solution.The following are the main research content and achievements in this paper:(1) Simulate the 3-D flow in the right-angle dig-in basin by combining three turbulence models with the VOF model of air-water two-phase flow. Then the numerical results are compared to the measured results, and the compare shows that the RNG k-εmodel is better than standard k-εmodel and Realizable k-εmodel in the numerical simulation of dig-in basin.(2) Describe the three-dimensional flow structure in the basin and analyzed the genetic mechanism and influencing factors by simulating the 3-D flow in the right-angle dig-in basin with RNG k-εmodel. Summarize the general rules of dig-in basin by analyzing the changes of 3-D flow structure in different boundary conditions and different current conditions.(3) On the basis of the study of three-dimensional flow structure in the basin and the previous study of silt sediment in dig-in basin, we propose three measures:a) adding a guide dike on the upstream basin; b) adding a anti-silt dike at the entrance section; c) adding a collected-silt pit in the inner side of entrance section. Then analyzed the relation between 3-D flow structure changes and silt sediment after taking the anti- silt sediment measures, to optimize the dig-in basin layout and anti-silt sediment measures.