Graduate School in Nonlinear Science

Sponsored by The Danish Research Agency


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

CONVECTIVE TRANSPORT AND SHEARED MEAN FLOWS

Odd Erik Garcia
Auroral Observatory,
University of Tromsų,
N-9037 Tromsų,
Norway
odd@phys.uit.no

Tuesday, December 18, 2001, 14:00 h
at OFD Meeting Room, Building 130
Risų National Laboratory, 4000 Roskilde

Abstract: This presentation concerns two-dimensional modelling and numerical simulations of buoyancy driven convection and non-linear transport. In particular the effects of thermal boundary conditions and sheared mean flows are investigated. For strong drive the transport becomes bursty and fluctuations intermittent. As the thermal flux through the system increases the system goes through different transport regimes exhibiting Gaussian fluctuations as well as PDF's with exponential tails and long-time correlations. The fluctuating sheared mean flows are found to be essential for controlling the turbulent fluctuations and hence the convective transport.