4:1椭球体分离流动湍流特性的试验研究  

EXPERIMENTAL INVESTIGATION ON TURBULENT BEHAVIORIN A SEPARATED FLOW AROUND A 4 : 1 PROLATESPHEROID AT INCIDENCE

作　　者：尹崇禄[1] 曹露洁[1] 林发布[1] 王凯建[1] 魏中磊[1] 孟庆国[2] 

机构地区：[1]北京大学湍流及复杂系统国家重点实验室,北京100871 [2]国家自然科学基金委员会数理科学部,北京100085

出　　处：《力学学报》2002年第4期501-507,共7页Chinese Journal of Theoretical and Applied Mechanics

基　　金：科技部1998年攀登预演基金资助项目

摘　　要：使用六线涡量探头,对α=30°条件下绕（4:1）椭球体分离流动的湍动能u’2,v’2,w’2,雷诺应力u’v’和涡量Ωx等进行了详尽的测量.应用频谱分析的方法揭示了绕（4:1）椭球体分离流内主附着涡外缘剪切层上的离散小涡的特性.The turbulent characteristics of turbulence energy u2,v2,w2, Reynolds stress u'v', u'w', v'w' and mean vorticity of stream-wise Ωx, span-wise Ωz and transverse-wise Ωy, as well as mean enstrophy and helicity in the separated flow field around a (4:1) prolate spheroid at α=30°incidence has been extensively measured by a six-sensor hot-wire probe. The frequency behavior of the stream-wise turbulence fluctuation u', measured by single hot-wire probe, in a separated flow over the lee-side around the prolate spheroid is analyzed by spectral method to reveal characteristics of the separated shear layer of passing small discrete vortices of the strong large-bound vortices. The experimental results exhibit that the high level of turbulent energy u2, v2 and Reynolds stress u'v' are mainly concentrated in the core domain of the spiral large-bound vortex over the lee-side of the flow field above the prolate spheroid. The results also show us that the out-edge of the strong large-bound vortices in the separated flow above the lee-side around a prolate spheroid can be successfully determined by spectrum analysis of the stream-wise turbulence fluctuation u', whose result is in good agreement with the distribution of the mean stream-wise vorticity Ωx measured by vorticity hot-wire probe and the visualization photo obtained by hydrogen bubble technique in a water tunnel. The outer-edge of separated shear layer around a (4:1) prolate spheroid at incidence consists of a series of passing discrete vortices just as the separated flow from a delta wing, which Prof. Mohamed Gad-el-Hak has pointed out.

关 键 词：湍流特性 椭球体分离流 离散小涡 涡量 螺度 六丝热线探头 频谱分析 

分 类 号：O357.5[理学—流体力学]