基于IDDES方法的冲刷地形海底管道绕流数值模拟  

Numerical simulation of flow around on a pipeline near a scoured bed based on IDDES method

作　　者：曲孟祥 杨博 梁丙臣[1,2] 刘欣 张嶔 QU Mengxiang;YANG Bo;LIANG Bingchen;LIU Xin;ZHANG Qin(College of Engineering, Ocean University of China, Qingdao 266100, China;Shandong Provincial Key Laboratory of Ocean Engineering, Qingdao 266100, China)

机构地区：[1]中国海洋大学工程学院,山东青岛266100 [2]山东省海洋工程重点实验室,山东青岛266100

出　　处：《海洋工程》2022年第2期97-105,共9页The Ocean Engineering

基　　金：国家自然科学基金项目(51739010)。

摘　　要：近年来,海底管道对于近海油气工业中碳氢化合物的运输十分重要,预测海底管道周围水动力特征对于研究管道损坏机理具有重要意义。基于Spalart-Allmaras改进延迟分离涡模拟(improved detached eddy simulation,简称IDDES)湍流模型,利用开源OpenFOAM求解器计算单管冲刷过程中4个特征阶段管道周围水动力特征。在数值模拟中先计算了无圆管时均匀来流充分发展后的流场,依据该流场中进口流速分布设定有管道时的边界层及进口边界条件。通过将最终模拟结果与前人试验数据及数值模拟结果进行对比,表明了该模型计算结果相对于k-ε模型及LES模型更加贴合试验结果,验证了定义边界层方法的可靠性及IDDES模型在预测管道周围流场的适用性。模型计算结果显示,随着冲刷坑深度的逐渐增加,管道下游回流区会经历一个大幅缩减又逐渐扩大的过程,且逐渐关于圆管中心所在水平线对称;通过对不同冲刷阶段尾涡形态的分析表明,冲刷前期并没有涡脱产生,中期已经有产生涡脱的趋势,后期出现了明显的且较为稳定的涡脱。The submarine pipelines are more and more important for the transportation of hydrocarbons in the offshore oil and gas industry.So the prediction of the hydrodynamic characteristics around pipelines is of great significance,and can help researchers study the damage mechanism of the pipeline.In this study,based on the Spalart-Allmaras IDDES(improved detached eddy simulation)turbulence model,the open source CFD code OpenFOAM was used to calculate the flow field around the pipeline over four scour beds.In the numerical simulation,the four cases without cylinder were firstly calculated.Based on the inlet velocity distribution of those cases,the boundary layer and inlet boundary condition of the cases with pipe were set.By comparing the simulation results with previous experimental data and numerical simulation results based on k-εmodel and LES model,it is shown that the calculated results of the IDDES model are more consistent with the experimental results,which verifies the reliability of the method used to define boundary layer and the applicability of IDDES model in predicting the hydrodynamic characteristics around the pipelines.The simulation results show that with the increase of the depth of scour hole,the downstream reflux area of the pipeline will experience a process of greatly shrinking and gradually expanding,and the wake flow will gradually approach symmetry.Through analyzing the shape of the trailing vortexes in different scoured beds,it is shown that there is no vortex shedding in the early scour stage,which tends to occur in the middle scour stage,and then appears obviously and stably in the late scour stage.

关 键 词：海底管道 冲刷 边界层 旋涡脱落 IDDES OPENFOAM 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]