Scalar dissipation fronts in high-Schmidt number mixing

Scalar dissipation fronts in high-Schmidt number mixing.

Jörg Schumacher Fachbereich Physik, Philipps-Universität Marburg, D-35032 Marburg, Germany Herwig Zilken Visualization Laboratory, Zentralinstitut für angewandte Mathematik, Forschungszentrum Jülich, D-52425 Jülich, Germany Bruno Eckhardt Fachbereich Physik, Philipps-Universität Marburg, D-35032 Marburg, Germany Katepalli R. Sreenivasan International Centre for Theoretical Physics, 34014 Triest...

Statistics and geometry in high-Schmidt number scalar mixing

The mixing of substances is present in various turbulent systems. Examples arise in reacting flows and combustion, mixing of salt and plankton in oceans and of chemical pollutants in the stratosphere [1]. The physics of scalar mixing depends strongly on the ratio of the kinematic viscosity ν of the fluid to the diffusivity κ of the scalar. It is given by the Schmidt number Sc = ν/κ. For the fol...

Reynolds number dependence of scalar fluctuations in a high Schmidt number turbulent jet

The scalar rms fluctuations in a turbulent jet were investigated experimentally, using highresolution, laser-induced fluorescence techniques. The experiments were conducted in a high Schmidt nuinber fluid (water), on the jet centerline, over a jet Reynolds number range of 3000<Re<24 000. It was found that the normalized scalar rms fluctuations c’/ C decrease with increasing flow Reynolds number...

High Rayleigh number convection and passive scalar mixing

A brief review is given of recent laboratory investigations of high Ra convection and their relation to other turbulent flows. For a passive scalar we summarize an emerging body of theory for the one point distribution function and inertial range correlation functions which display non-Kolmogorov exponents. Low R a number convection has long been the system of choice for investigating the onset...

On filtering in the viscous-convective subrange for turbulent mixing of high Schmidt number passive scalars