Late-Stage Vortical Structures and Eddy Motions in a Transitional Boundary Layer
LIU Xiao-Bing1,2, CHEN Zheng-Qing1, LIU Chao-Qun2
1Wind Engineering Research Center, Hunan University, Changsha 4100822Department of Mathematics, University of Texas at Arlington, Arlington, Texas 76019, USA
Late-Stage Vortical Structures and Eddy Motions in a Transitional Boundary Layer
LIU Xiao-Bing1,2, CHEN Zheng-Qing1, LIU Chao-Qun2
1Wind Engineering Research Center, Hunan University, Changsha 4100822Department of Mathematics, University of Texas at Arlington, Arlington, Texas 76019, USA
摘要A high-order direct numerical simulation of flow transition over a flat-plate at a free stream Mach number 0.5 is carried out. Formation and development of three-dimensional vortical structures, typically shown as λ-vortices, hairpin vortices and ring-like vortices, are observed. Numerical results show that there is a strong downdraft motion of fluid excited by every ring-like vortex in the late-stage of the transition process. At two sides of the vortical structure centerline, the downdraft motions induced by the ring-like vortex and the rotating legs superimpose. This is responsible for the appearance of a high-speed streak associated with the positive spike observed in a previous investigation and the appearance of a high-shear layer in the near wall region.
Abstract：A high-order direct numerical simulation of flow transition over a flat-plate at a free stream Mach number 0.5 is carried out. Formation and development of three-dimensional vortical structures, typically shown as λ-vortices, hairpin vortices and ring-like vortices, are observed. Numerical results show that there is a strong downdraft motion of fluid excited by every ring-like vortex in the late-stage of the transition process. At two sides of the vortical structure centerline, the downdraft motions induced by the ring-like vortex and the rotating legs superimpose. This is responsible for the appearance of a high-speed streak associated with the positive spike observed in a previous investigation and the appearance of a high-shear layer in the near wall region.
LIU Xiao-Bing;CHEN Zheng-Qing;LIU Chao-Qun. Late-Stage Vortical Structures and Eddy Motions in a Transitional Boundary Layer[J]. 中国物理快报, 2010, 27(2): 24706-024706.
LIU Xiao-Bing, CHEN Zheng-Qing, LIU Chao-Qun. Late-Stage Vortical Structures and Eddy Motions in a Transitional Boundary Layer. Chin. Phys. Lett., 2010, 27(2): 24706-024706.
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2010, Vol. 27 
