Graduate School in Nonlinear Science

Sponsored by the Danish Research Academy

MIDIT                               OFD                           CATS
Modelling, Nonlinear Dynamics       Optics and Fluid Dynamics     Chaos and Turbulence Studies
and Irreversible Thermodynamics     Risø National Laboratory      Niels Bohr Institute and 
Technical University of Denmark     Building 128                  Department of Chemistry
Building 321                        P.O. Box 49                   University of Copenhagen 
DK-2800 Lyngby                      DK-4000 Roskilde              DK-2100 Copenhagen Ø
Denmark                             Denmark                       Denmark

Chaotic advection and transport in a Hamiltonian map

Abstract: We present an introduction to techniques developed to understand chaotic advection and transport in Poincare maps of time periodic flows. We then apply these techniques to the problem of pollution in a turbulent estuarine flow. In particular we look at the problems of patchiness in clouds of pollution and also the optimal discharge of pollution (ie. sewage or effluent etc.) into such a flow.

Chaotic advection and transport in a non-area preserving map

Abstract: We extend the techniques developed in the first talk to look at chaotic advection, bifurcation and transport on the bounding surface of a fully coupled 3-dimensional map of our estuarine flow. For non slip boundary conditions in a fluid flow such surfaces are 2-dimensional invariant manifolds on which the flow is generically non-area preserving and hence due to the time periodicity can be reduced to a 2 dimensional non-area preserving Poincaré map. We then apply these techinques to the problems of patchiness and optimal discharge of pollution in our estuarine flow.