Abstract
This chapter illustrates the nonintrusive analysis of parametric uncertainty. Quantification of spectral modes adds a new level of understanding, identifying the significance of individual uncertain parameters and determining where within the evolution of the system each parameter has the most influence. In this study, a technique of uncertainty quantification through spectral projection methods is used to examine the propagation of parametric uncertainty through 0D combustion chemistry and 1D premixed flame, with a focus on higher-order information and the correlations among parameters. Compared to conventional Monte Carlo analysis, this method quantifies the extent, dependence, and propagation of uncertainty through the model system and allows correlation of uncertainties in specific parameters to the resulting total uncertainty in product concentrations and flame structure. Analysis of 0D and 1D hydrogen-oxygen combustion demonstrates that known empirical uncertainties in model parameters may result in large uncertainties in the final output, and nonlinearities in system response behavior make the order of the analysis an important consideration. Furthermore, this analysis is readily extendable to multiple dimensions and greater numbers of uncertain parameters, while preserving the integrity of the realization engine through the nonintrusive operation of the method.