This report discusses direct numerical simulations (DNS) of a mixing layer, between a nitrogen stream and a heptane stream initially flowing at different velocities, under supercritical conditions and undergoing a transition to turbulence. Thermodynamically, supercritical conditions prevail when either the temperature or the pressure exceeds its critical value; the critical regime is in particular characterized by the existence of a single phase. The governing conservation equations were formulated according to fluctuation-dissipation (FD) theory, in which the low-pressure typical transport properties (viscosity, diffusivity, and thermal conductivity) are complemented, at high pressure, by a thermal-diffusion factor.

This work was done by Josette Bellan and Nora Okong'o of Caltech for NASA's Jet Propulsion Laboratory. To obtain a copy of the report, "Direct Numerical Simulation of a Transitional Supercritical Mixing Layer: Heptane and Nitrogen," access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp  under the Physical Sciences category.

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