Direct Numerical Simulation Investigation of the Conditional Moment Closure Model for Nonpremixed Turbulent Reacting Flows

Abstract By using direct numerical simulations (DNS), the accuracy of the Conditional Moment Closure Model (CMC) is tested for a nonpremixed reaction in decaying, spatially homogeneous turbulence. Simple one step, second order, irreversible, isothermal chemistry is used. The model equation is solved in two ways:(a) assuming that the mixture fraction and its dissipation are statistically independent, (b) accounting for their statistical dependence via a shape factor. In both cases (a) and (b) the predicted mean of the fuel mass fraction agreed well with the DNS data. Predictions obtained using approximation (b) were somewhat better than those using approximation (a).