Dear All, Next week, Friday 11th October, Jack Xin (UC Irvine) will give a talk at USyd in Carslaw 275 at 4pm on Title: Enhanced Diffusivity in Chaotic Flows Abstract: Transport phenomena in fluid flows are observed ubiquitously in nature such as smoke rings in the air, pollutants in the aquifers, plankton blooms in the ocean, and stirring drops of cream in a cup of coffee. We begin with examples of two dimensional Hamiltonian systems modelling incompressible planar flows, and illustrate the transition from ordered to chaotic flows as the Hamiltonian function becomes more time dependent. We introduce effective diffusivity via Lagrangian and Eulerian formulation, and show how its enhancement relate to the existence of periodic orbits (order) and chaotic behavior of flow trajectories (disorder). Then we discuss enhanced diffusivity in three dimensional chaotic flows, viz., the Arnold-Beltrami-Childress flow and the Kolmogorov flow, through structure-preserving schemes. Hope to see you all there, Lachlan