| Abstract: | A physical mechanism of onset of large-scale organized structures in turbulent flows along a plane wall which are the cause
of intensification of turbulent fluctuations is formulated. The structures take the form of high-speed and low-speed streaks
caused by streamwise vortices, i.e., motions in the plane of the transverse cross-section. The streamwise vortices are excited
as a result of instability under the action of the anisotropy of the normal components of the Reynolds stress tensor. A model
for describing these vortices that gives characteristics in qualitative and quantitative agreement with the experimental data
is proposed. In particular, the most probable and mean distances between neighboring vortices are correctly reproduced. The
theory makes it possible to explain certain methods of turbulent flow control for the purpose of drag reduction.
Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 24–30, January–February,
1997.
The work was carried out with financial support from the Russian Foundation for Fundamental Research (project No. 96-01-00602). |
