冲刷地形下近壁面串列双圆管绕流问题的数值模拟  

Numerical Simulation of Flow Around Two Cylinders in Tandem Near a Scoured Bed

作　　者：鲁小辉 张嶔[2] 杨博 梁丙臣[2,3] Lu Xiaohui;Zhang Qin;Yang Bo;Liang Bingchen(Safety Supervision Department Sinopec, Beijing 100728, China;College of Engineering, Ocean University of China, Qingdao 266100, China;Shandong Provincial Key Laboratory of Ocean Engineering, Ocean University of China, Qingdao 266100, China)

机构地区：[1]中国石油化工集团有限公司安全监管部,北京100728 [2]中国海洋大学工程学院,山东青岛266100 [3]中国海洋大学山东省海洋工程重点实验室,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2022年第5期114-121,共8页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(51739010)资助

摘　　要：为探究复杂地形条件对串列双圆管局部流场及圆管受力特征的影响,本文基于Spalart-Allmaras改进延迟分离涡模拟(Improved detached eddy simulation,IDDES)湍流模型,利用开源OpenFOAM求解器模拟了7种不同水平间距条件下串列双圆管在冲刷地形下的流场特征。分析了在不同水平间距条件下,上、下游圆管的受力特征、平均流场特征及瞬时涡量场特征,探究了双圆管下方冲刷坑的成因。模型结果显示,在冲刷地形下,随着两管之间水平间距的变化,两圆管的尾迹同样会经历从延伸体流态到重新附着流态,最后发展至共同脱落流态的变化。在冲刷地形条件下,上游圆管会受到一个流体施加的向下作用力。当两管尾迹处于重新附着流态时,上游圆管的涡脱落会被抑制,下游圆管在较小的水平间距条件下会受到一个负向的拖曳力,随着水平间距的增大逐渐转为正向。通过对平均流场和瞬时涡量场的分析可知,在水平间距较小的情况下,冲刷坑的形态主要受制于平均水流。而在水平间距较大的情况下,下游冲刷坑的发展主要受到上游圆管涡脱落的影响。To investigate the effect of complex topography conditions on the flow field and force characteristics of tandem cylinders. In this paper, based on the Spalart-Allmaras IDDES turbulence model, the open source CFD code OpenFOAM is used to calculate the flow field around the pipelines in tandem over scour beds under 7 different horizontal spacing conditions. The force characteristics of the upstream and downstream cylinders, average flow field and instantaneous vortex field characteristics under different horizontal spacing conditions were analyzed, and the causes of the scour holes below the cylinders were investigated. The model results show that under the scouring bed, with the change of horizontal spacing between the two cylinders, the wake of the two cylinders will undergo a change from the extended body regime to the reattachment regime and finally develop to the co-shedding regime. Under scouring bed conditions, the upstream cylinder is subjected to a downward force exerted by the fluid, and under reattachment regime the vortex shedding of the upstream cylinder is suppressed. And the downstream cylinder will be subject to a negative drag force under the condition of smaller horizontal spacing, and gradually turn to positive with the increase of horizontal spacing. The analysis of the mean flow field and the instantaneous vortex shows that the morphology of the scour holes is mainly influenced by the mean flow in the case of small horizontal spacing. And in the case of large horizontal spacing, the morphology of the downstream scour hole is mainly influenced by the vortex shedding form upstream cylinder.

关 键 词：串列双圆管 边界层 涡脱落 流动分离 改进延迟分离涡模拟 OpenFOAM求解器 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]