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
TWO-DIMENSIONAL NAVIER-STOKES TURBULENCE WITH MATERIAL WALLS
by David C. Montgomery
Dartmouth, USA
Wednesday October 13, 1999, 10:30 h
NBI, University of Copenhagen
Abstract: Most theoretical considerations of turbulence have been set in the
"homogeneous turbulence" framework, in which spatially periodic boundary
conditions are assumed for all time over a very large box with rectangular
symmetry. Rather different results emerge when turbulent decays are computed
inside rigid no-slip or stress-free material boundaries. Particularly in the
two-dimensional case, it is possible to argue that no material container,
however large, will ever lead to the same results as are now regularly seen
in periodic geometry. One reason is the dominant role that angular momentum
(nearly conserved by circular walls, generated by rectangular ones) seems to
play in governing the decay. Computations at higher Reynolds numbers than
have been carried out so far seem to be desirable. There are also unresolved
problems associated with determinations of the pressure.
References: Shuojun Li, David Montgomery, and Wesley Jones, Theoretical and
Computational Fluid Dynamics 9, 167 (1997); and Physics Letters A218, 281
(1996).