丁坝冲刷的三维紊流模拟研究

Numerical simulation on scour around spur-dike by 3D turbulent model

丁坝附近的流态和冲刷情况在工程中一直受到人们的重视。本文采用三维RNG紊流模型,结合璧面函数法,利用VOF方法和空度方法处理不规则边界、河床变形及自由水面,采用不平衡推移质输沙模型,同时考虑床面坡度对推移质输沙及临界启动切应力的综合影响,精细模拟了丁坝附近的流场、地形冲淤变化、冲刷坑形态等,并把计算结果与实验资料进行了对比分析,二者吻合较好。模型准确的反映了丁坝局部流态、冲刷的过程和特征。

The prediction of the flow field around spur-dikes and circumfluence region and scoured of fiver bed is very important for some hydro-engineering problems. A 3D turbulent model was adopted to simulate flow field and scoured hole around spur-dike. The flow field and characteristic of local scour-deposition around spur dike, such as bed contours, topography of scouring hole, were subtly simulated. In the model, RNG k - ε model and the wall function method were adopted. At the same time, the porosity and VOF method were used to deal with some complex conditions such as irregular boundary, fiver bed deformation and free water surface. To the sediment, the non-equilibfium bed-load transport model is adopted. At the same time, the influence of bed slope on bed-load transport and critical startup shear stress was considered. Then comparing the results with experimental data, it was shown that they agree well. It indicates that the model can simulate the flow field and scouting processing well around sour-dike.