A report describes direct numerical simulations of a droplet-laden mixing layer (e.g., evaporating droplets of a hydrocarbon fuel in air) undergoing a transition to mixing turbulence. The governing equations are those of Lagrangian transport of discrete droplets through a flowing gas, which is represented by Eulerian equations with source terms for two-way couplings of mass, momentum, and energy among the liquid, vapor, and carrier-gas phases. The equations are solved numerically, using as many as 18 × 106 grid points to discretize the Eulerian gas-phase equations and tracking as many as 5.7 × 106 evaporating droplets of various initial sizes in the Lagrangian reference frame.
This work was done by Josette Bellan and Richard Miller of Caltech for NASA's Jet Propulsion Laboratory. To obtain a copy of the report, "Direct numerical simulation and subgrid analysis of a transitional droplet laden mixing layer," access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Physical Sciences category. NPO-20709
