Topological evolution of laminar juncture flows under different critical parameters

作     者：YOUNIS Muhammad Yamin ZHANG Hua HU Bo MEHMOOD Saqib 

作者机构：National Key Laboratory of Fluid Mechanics School of Aeronautical Science and Engineering Beihang University School of Astronautics Beihang University 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2014年第57卷第7期

页      面：1342-1351页

核心收录：

学科分类：080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0801[工学-力学（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.11372027) 

主　　题：horseshoe vortex saddle of attachment saddle of separation topological evolution sweeping effect 

摘      要：Horseshoe vortex topological structure has been studied extensively in the past,traditionalsaddle of separationand newattachment saddle pointtopologies found in literature both have theoretical basis and experimental and computational evidences for *** laminar incompressible juncture flows at low Reynolds numbers especially are observed to have new *** concerning the existence of the new topology though found in literature,the topological evolution and its dependency on various critical flow parameters require further investigation.A Particle Image Velocimetry based analysis is carried out to observe the effect of aspect ratio,?*/D and shape of the obstacle on laminar horseshoe vortex topology for small *** in aspect ratio evolves the topology from the traditional to new for all the cases *** circular cross section obstacles are found more apt to having the new topology compared to square cross *** is noted that the sweeping effect of the fluid above the vortex system in which horseshoe vortex is immersed plays a critical role in this *** evolution is observed not only in the most upstream singular point region of horseshoe vortex system but also in the corner *** corner vortex topology evolves from the traditional type to new one before the topological evolution of the most upstream singular point,resulting in a new topological pattern of the laminar juncture flowsseparation-attachment combination.The study may help extend the understanding of the three-dimensional boundary layer separation phenomenon.