We present the application of orthogonal wavelet filtering to study
mixing and chemical reaction in 2D turbulent flows. We show that
the coherent vortices are responsible for the mixing dynamics.
Therefore, we perform direct numerical simulation of decaying and
statistically stationary homogeneous isotropic 2D turbulence. We
split the flow in each time step into coherent vortices represented
by few wavelet modes and containing most of the kinetic energy and
an incoherent background flow. We quantify the mixing properties of
both flow components and demonstrate that efficient mixing of
scalars is triggered by the coherent flow, while the influence of
the incoherent flow on the mixing corresponds to pure diffusion.
These results hold for both passive scalars and reactive scalars
with simple and multi-step kinetics.
Chemical Engineering Science 58 (2003) 1463 – 1477
Chemical Engineering Science 58 (2003) 1463 – 1477