Uncertainty Quantification of a Rotorcraft Conceptual Sizing
A computational framework to support the quantification of system uncertainties and sensitivities for rotorcraft applications is presented using the NASA Design and Analysis of Rotorcraft (NDARC) conceptual sizing tool. A 90 passenger conceptual tiltrotor configuration was used for case demonstration in the modeling of uncertainties in NDARCs emission module. A non intrusive forward propagation uncertainty quantification approach was applied to ensemble simulations using a Monte Carlo methodology with stratified Latin hypercube sampling. An off the shelf software, DAKOTA, which supports trade studies and design space exploration, including optimization, surrogate modeling and uncertainty analysis, was used to address the research goals. Further, a toolsuite was developed incorporating DAKOTA with automated design processes and methods using function wrappers to execute program routines including support for data post processing. Uncertainties in rotorcraft emissions modeling using the Average Temperature Response metric for a set mission profile were studied. NDARC under estimates the effects of emissions when using the baseline modeling parameters for the Average Temperature Response compared with mean results from Monte Carlo simulations. A global sensitivity analysis was further undertaken to quantify the contribution of the various emission species on output sensitivity. The work demonstrates that the developed toolsuite is robust and could support the quantification of system uncertainties and sensitivities in future rotorcraft design efforts.