2019/01/17 by Masaki Shimizu, Takahiro Kanazawa, Genta Kawahara · 13 citations
paper · doi:10.1088/1873-7005/aaa73c
published in Fluid Dynamics Research 51(1), 011404 (IOP Publishing)
crossref created 2018/01/12 · crossref issued 2019/01/17 · crossref published 2019/01/17 · crossref published-online 2019/01/17 · crossref published-print 2019/02/01 · crossref deposited 2026/03/14 · crossref indexed 2026/07/31
Abstract The transition to turbulence in wall-bounded flows, for example pipe flow, plane Couette flow and channel flow, initially occurs as localized clusters of turbulence. It is well known that these localized structures are transient and decay in a memoryless process. In this paper we investigate the relationship between the extent of a localized structure and its lifetime. By performing numerical simulations of channel flow with small spanwise periodicity we produce streamwise-localized but spanwise-extended turbulence, turbulent ‘puffs’ instead of spots. We vary the spanwise periodzation length as the parameter of its extent to show that the lifetime of turbulent ‘puffs’ increases double-exponentially as a function of the Reynolds number for any spanwise extent. It is also shown that the lifetime increases exponentially as a function of the spanwise size when it is not large.