Influence of the surface roughness on the third-order moments of velocity fluctuations

被引:12
作者
Keirsbulck, L [1 ]
Mazouz, A [1 ]
Labraga, I [1 ]
Tournier, C [1 ]
机构
[1] Univ Valenciennes, Lab Mecan Fluides & Energet, F-59304 Valencienne, France
关键词
D O I
10.1007/s003480000177
中图分类号
TH [机械、仪表工业];
学科分类号
0802 ;
摘要
Roughness wall effects in a zero pressure gradient turbulent boundary layers were investigated using hot-wire anemometry. The skewness and diffusion factors of u and v, the longitudinal and normal velocity fluctuations, were measured and represented using wall variables. The results indicate that the wall roughness removes the crossover point between sweep and ejection events to the outer region of the layer for a single Reynolds number Re-theta > 3,000. This behaviour exhibits that the roughness surface favours the maintaining of sweep events obtained by a quadrant analysis. These results show that communication between the wall region and outer region of a turbulent boundary layer exists and the wall similarity hypothesis for a rough wall is questionable. The effect of the wall roughness on the position of the point crossover from sweep to ejection motions with respect to the wall seems to be the same as that obtained when the Reynolds number is higher.
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页码:592 / 594
页数:3
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