THEORY, MODELING AND ANALYSIS OF TURBULENT SUPERCRITICAL MIXING

ABSTRACT

Previous studies of supercritical three-dimensional mixing layers are reviewed to derive a unified understanding of supercritical turbulence and mixing. These studies consisted of Direct Numerical Simulations of mixing layers having initially a single chemical species in each of the two free streams. Each mixing layer was initially perturbed, which led to a double pairing of four initial spanwise vortices. These pairings yielded in each case an ultimate vortex within which small scales proliferated, resulting in a state having turbulence characteristics, called a transitional state. The evolution of the layer to this transitional state and the state itself were previously analyzed to elucidate the features of supercritical turbulence and mixing. This analysis is here used to classify those supercritical turbulent mixing characteristics that are species-system independent or species-system dependent. Finally, comments are offered on future prospects of developing small-scale models particularly suited for Large Eddy Simulations of supercritical turbulent mixing.

Keywords:

• high-pressure turbulence
• mixing

This study was conducted at the Jet Propulsion Laboratory (JPL), California Institute of Technology (Caltech) and sponsored by the National Aeronautics and Space Administration (NASA), under the Microgravity Fluids Program with Dr. Walter Duval as Program Manager. The author wishes also to acknowledge Drs. Ken G. Harstad and Nora A. Okong'o of JPL for interesting discussions during the course of collaboration on studies of supercritical flows.

Notes

*Harstad and Bellan, 2000.

**Harstad and Bellan, 1998; Harstad and Bellan, 2001b.