Repeller or attractor? Selecting the dynamical model of shear flow turbulence
Seminar Room 1, Newton Institute
The collapse of turbulence, observable in shear flows at low Reynolds numbers, raises the question if turbulence is generically of transient nature or becomes sustained at some critical point. Recent data have lead to conflicting views with the majority of studies supporting the model of turbulence turning into an attracting state. Here we present lifetime measurements of turbulence in pipe flow spanning eight orders of magnitude in time, drastically extending all previous investigations. We show that no critical point exists in this regime and that in contrast to the prevailing view the turbulent state remains transient. The observed transient scaling behaviour has been conjectured to occur in turbulent flows more than two decades ago.