A stochastic flamelet progress-variable approach for numerical simulations of high-speed turbulent combustion under chemical-kinetic uncertainties

In this study, a flamelet-based framework is proposed for quantifying the uncertainties induced by chemical-kinetic rates on the aerothermochemical field in numerical simulations of high-speed turbulent combustion. For this purpose, this report is divided into the following sections. In Section 2, a short background on flamelet physics is provided. In Section 3, the RANS formulation of the outer problem is summarized. In Section 4 the flamelet progress-variable approach (FPVA) for modeling turbulent combustion (Pierce & Moin 2004) is extended to treat uncertainties in chemical kinetics. In Section 5, a strategy for propagating input uncertainties in the main aerothermochemical variables is proposed. Section 6 is focused on a short assessment of the potential effects of chemical-kinetic uncertainties in the hydrogen-fueled Hyshot-II SCRAMJET engine. Finally, conclusions are drawn in Section 7. This work is founded upon another article that appears in this same volume (Urzay et al. 2012) for quantifying uncertainties in chemical-kinetic rates.