"Decomposition of Mixing Layer Turbulence into Coherent
Structures and Background Fluctuations"
by
Lewalle, J., Delville, J. and Bonnet, J.P.
ABSTRACT
The eduction of coherent structures from cross-wire rake data
in a fully turbulent incompressible mixing layer confirms
the feasibility of a decomposition of a turbulent flow field,
first suggested by Farge, as non-periodic non-equilibrium
coherent structures interacting with a `thermalized' broad-band
turbulence. A simple wavelet coefficient decimation algorithm
and orthogonalization yields non-periodic dominant flow structures.
The coherent structures are classified
in terms of their topology. The non-coherent background field has
flat energy spectra and normal distribution of velocity components.
Most background field statistics depend only weakly on
the type of structure on which they are superposed.
It may be possible to adapt existing subgrid scale models
to this decomposition.
to appear, Flow Turbulence and Combustion, 2000.
Jacques Lewalle, jlewalle@syr.edu
