%0 Journal Article
%T A 3-D WAVE MODEL FOR THE COHERENT STRUCTURES[1mm］ IN THE OUTER REGION OF A TURBULENT[1mm］ BOUNDARY LAYER<br>湍流边界层外区相干结构的三维波模型
%A LU Lipeng
%A LUO Jisheng
%A <br>陆利蓬
%A 罗纪生
%J 力学学报
%D 2000
%I 
%X Based on the theory of hydrodynamic instability, a new theoretical modelcontaining a 2-D wave and a pair of 3-D waves was proposed for thecoherent structures in the outer region of a turbulent boundary layer.In calculation, we assumed that the Reynolds stresses induced bysmall-scale eddies acting on the large-scale eddies can be expressed byeddy viscosity model, where the complex eddy viscosity is used to embodythe lag of the stresses to the deformation of large-scale eddies.According to the experiments that the scale of the coherent structuresin the streamwise is about 2, the streamwise wave number of the waves ischosen as 2π/=3.14. At present, there have been no experimental results aboutthe spanwise wave number. In this paper, several cases with differentspanwise numbers were computed. The results showed that both thestreamlines and the isovorticity lines obtained were in good agreementwith those of experimental observations only when the spanwise number of3-D wave was about half of the streamwise number. The streamlines andisovorticity lines for four different Reynolds numbers R=11800,19005, 47949 and 84427 were calculated. The results agree with theexperimental results much better than those by 2-D wave model.It is can concluded that large-scale coherent structures in the outerregion of a turbulent boundary layer can be described by the unstablewave model. The 3-D model proposed in this paper can correctly describethe physical mechanism of the coherent structures in the outer region ofa turbulent boundary layer.
%K outer region
%K turbulent boundary layer
%K coherent structures
%K 3-D wave<br>湍流边界层外区
%K 相干结构
%K 三维波模型
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=5D344E2AD54D14F8&jid=4100DA4A1A3BA1B0CE5AD99AE1DFB420&aid=142FEBCAFEA75C9C&yid=9806D0D4EAA9BED3&vid=9971A5E270697F23&iid=B31275AF3241DB2D&sid=195767709E606C85&eid=762CFFBBDED11937&journal_id=0459-1879&journal_name=力学学报&referenced_num=2&reference_num=2