The model is a vertical 2D numerical model based on the revised NS equation. The Particles Level Set method is adopted for the free surface simulation and the suspended silt motion is simulated by convection and diffusing equation. The bed distortion is calculated according to the principle of bed material equilibrium and the bed scouring and silting induced by water flow is simulated. The model make water flow model extend to the field of silt motion. The notion of two phase flow is used to simplify free water surface boundary condition,simulate the suspended silt, bed silt and bed distortion. Computer re-meshing is not required because a fixed Cartesian coordinate is used, which can easily dealt with the reciprocity of liquid, sediment and structure. The examples of off-siltation when the flow with sediment goes through a trench and the local scour around a pipeline foundation by water flow are applied to verify its rationality. Aiming at the problem silt surface may be larger than angle of repose during bed distortion that will induce the slope slide, the virtual time is suggested to be used.%本模型为垂向二维数学模型,以修正的NS方程为基础,采用粒子Level Set方法和对流扩散方程分别模拟自由水面和悬沙运动,根据底床物质质量平衡的原则计算底床变形,可模拟水流引起的底床冲淤变化.该模型将水流模型扩展到泥沙运动领域,以二相流概念简化自由水面边界条件,模拟悬沙、底沙和底床变形;采用固定的笛卡尔坐标,不需重新划分计算网格,可方便地处理流体-泥沙-结构之间的相互作用;并以含沙水流穿越航道挖槽的落淤和在水流作用下管线基础局部冲刷为应用实例,验证其合理性.针对床面变形过程中可能出现泥沙坡面大于泥沙休止角,进而引发滑坡的情况,建议以虚拟时间法进行相应处理.
展开▼
