海底振动管道局部泥沙冲刷数值研究

文章基于迎风有限元方法,对流动方程和泥沙输运方程进行求解,建立起振动管道与泥沙冲刷的耦合运动模型。模型中通过SST k-ω湍流模型对湍流效应进行模拟;管道振动和海床变形引起的不确定边界通过ALE方法进行实时追踪;模型考虑了悬移质输沙率以及推移质输沙率对底床变形的影响作用。数值模型首先与其他已发表的数据进行了比较,表明文章所建立的振动管道局部冲刷程序能够对冲刷深度进行较为准确地预测。文章利用所建数值模型进一步对海底振动管道局部冲刷问题开展了数值研究。相关数值分析结果表明:相对于固定管道的情况,管道振动对局部冲刷有较大的影响作用,管道的振动使管道局部最大冲刷深度增大,管道后方冲刷范围变宽,最大冲刷深度位置后移。

Numerical investigation of local scour around a vibrating pipeline under steady current

A two-dimensional finite element numerical model was developed to predict local scour around a vibrating submarine pipeline in steady current.The numerical model is based on the two-dimensional Navier-Stokes equations with Shear-Stress Transport(SST)k-ωturbulence model closure.Both suspended load and bed load sediment transportations were considered.The moving boundaries induced by the vibrating pipeline and the evolution of the seabed due to local scour were tracked by using the Arbitrary Lagrangian-Eulerian(ALE)method.Comparisons with the available experimental data show satisfactory agreements.The numerical model was then used to investigate local scour around a vibrating pipeline.Present numerical results show that vibrating of the pipeline makes the scour depth deeper,scour scope behind the pipeline wider and location of the maximum scour depth to the rear of the pipeline compared with the case of fixed pipeline.