Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN Print: 1-56700-135-1

TURBULENT SCALAR MIXING IN COAXIAL JET FLOWS

Sinopsis

The turbulent characteristics of the developing region of an axisymmetric coaxial jet of C02 (Rei= 15000) and air (Reo=50000) are analysed making use of experimental results obtained in the initial region where most of the mixing takes place. Time-resolved velocity and scalar fields were characterised by laser Doppler velocimetry and laser Rayleigh scattering, while the instantaneous velocity field was analysed with double-exposure photographic particle image velocimetry. Linear imaging of laser Rayleigh scattering was used to acquire instantaneous information about the scalar field that enables the quantification of scalar dissipation. As a result, scalar dissipation distribution can be associated to the evolution of the Reynolds stresses along the jet and the later is related to the location of large-scale structures, which are identified with the locus of maximum vorticity.