Center for the Study of Complex Systems
Seminar Series
Speaker: Robert Ecke
Director, Center for Nonlinear Studies
Las Alamos National Laboratory, NM
1085 S. University Ave., Ann Arbor, MI 48109-1107
Abstract: Fluid turbulence is central to transport and mixing in many
contexts from atmospheres and oceans to internal combustion vehicles.
Turbulence in three spatial dimensions is dominated by the net
transfer of kinetic energy from large scales to small scales where it
is dissipated as heat. In contrast, conservation laws in two
dimensions lead to a very different scenario, namely that energy flows
to larger scales whereas the flow to smaller scales is dominated by a
process of vortex gradient stretching. I will discuss the
characteristics of 2D turbulence and its applicability (or not) to
atmospheres and oceans where lateral extent is large compared to
vertical height. Because 2D turbulence technically only occurs in a
computer, quasi-2D experiments that are well described by 2D
turbulence phenomenology suggest its relevance to real physical
systems. In particular, I will describe experiments in flowing soap
films and in electrically forced thin salt layers that show remarkable
correspondence to the theory and numerical simulation of 2D
turbulence.
Complex System Seminar Series
