Soot formation in flames is an important physical process as it accounts for the majority of flame radiation and is a pollutant. Soot is a particulate species with a low diffusivity resulting in strong differential transport between soot and gaseous species comprising the flame which affects soot temperature, formation and destruction, and emission. Modeling these processes in turbulent flames is aided by direct numerical simulation. The image at right shows a two-dimensional nonpremixed ethylene flame decaying turbulence. Soot mass fraction is shown along with the stoichiometric isocontour colored by the relative velocity between the soot and the flame.