Extension at the downstream end of turbulent band in channel flow

Jinsheng Liu, Yue Xiao, Linsen Zhang, Mogeng Li, Jianjun Tao*, Shengjin Xu

*Corresponding author for this work

Research output: Contribution to journalLetterScientificpeer-review


In this Letter, the velocity structures and the extension behavior of localized turbulent bands in channel flows are measured by particle image velocimetry in a plane parallel to the walls and are analyzed by comparing with direct numerical simulations at low Reynolds numbers. It is illustrated that the convection velocity of the band head (band's downstream end) is not determined by the formation and propagation of low-speed streaks but by a high-speed "hat"shaped region near the band head. This "hat"region travels downstream obliquely like a solitary wave and leaves newly generated low-speed streaks to travel slowly in the spanwise direction, leading to the head extension of turbulent bands.

Original languageEnglish
Article number121703
JournalPhysics of Fluids
Issue number12
Publication statusPublished - 2020
Externally publishedYes


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