Allgemeines Physikalisches Kolloquium im Wintersemester 2011/2012
Ort: 48149 Münster, Wilhelm-Klemm-Str. 10, IG I, HS 2,
Zeit: Donnerstag, 03.11.2011 16:00 Uhr c.t.
Kolloquiums-Kaffee ab 15:45 Uhr vor dem Hörsaal
Resolving Reynolds Riddle
Dr. Björn Hof, Max-Planck-Institut für Dynamik und Selbstorganisation Göttingen
Shear flows undergo a sudden transition from laminar to turbulent motion as the velocity increases, and the onset of turbulence radically changes transport efficiency and mixing properties. Even for the wellstudied case of pipe flow, it has not been possible to determine at what Reynolds number the motion will be either persistently turbulent or ultimately laminar. We show that in pipes, turbulence that is transient at low Reynolds numbers becomes sustained at a distinct critical point. Through extensive experiments and computer simulations, we were able to identify and characterize the processes ultimately responsible for sustaining turbulence. In contrast to the classical Landau-Ruelle-Takens view that turbulence arises from an increase in the temporal complexity of fluid motion, here, spatial proliferation of chaotic domains is the decisive process and intrinsic to the nature of fluid turbulence.
Einladender: Prof. Dr. R. Friedrich
Im Auftrag der Hochschullehrer des Fachbereichs Physik
Prof. Dr. Sergej Demokritov