A mixed (aleatory and epistemic) uncertainty quantification (UQ) method was applied to computational uid dynamics (CFD) modeling of a synthetic jet actuator. A test case, (ow over a hump model with synthetic jet actuator control) from the CFDVAL2004 work-shop was selected to apply the Second-Order Probability framework implemented with a stochastic response surface obtained from Quadrature-Based Non-Intrusive Polynomial Chaos (NIPC). Three uncertainty sources were considered: (1) epistemic (model-form) uncertainty in turbulence model, (2) aleatory (inherent) uncertainty in free stream veloc-ity and (3) aleatory uncertainty in actuation frequency. Uncertainties in both long-time averaged and phase averaged quantities were quantified using a fourth order polynomial chaos expansion (PCE). A global sensitivity analysis with Sobol indices was utilized to rank the importance of each uncertainty source to the overall output uncertainty. The results indicated that for the long-time averaged separation bubble size, the uncertainty in turbulence model had a dominant contribution, which was also observed in the long-time averaged skin friction coeficients at three selected locations. The mixed uncertainty results for phase averaged x-velocity distributions at three selected locations showed that the 95% confidence interval (CI) could generally envelope the experimental data. The Sobol indices showed that near the wall, the uncertainty in turbulence model had a main inuence on the x-velocity, while approaching the main stream, the uncertainty in free stream velocity be-came a larger contributor. The mixed uncertainty quantification approach demonstrated in this study can also be applied to other computational uid dynamics problems with inherent and model-form input uncertainities.
D. F. Han and S. Hosder, "Inherent and Model-Form Uncertainty Analysis for CFD Simulation of Synthetic Jet Actuators," Proceedings of the 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition (2012, Nashville, TN), American Institute of Aeronautics and Astronautics (AIAA), Jan 2012.
The definitive version is available at http://dx.doi.org/10.2514/6.2012-82
50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition (2012: Jan. 9-12, Nashville, TN)
Mechanical and Aerospace Engineering
Keywords and Phrases
Aleatory uncertainty; CFD simulations; Confidence interval; Dominant contributions; Fourth order polynomial; Free stream; Free-stream velocity; Global sensitivity analysis; Non-intrusive; Polynomial chaos; Second orders; Separation bubble; Stochastic response surfaces; Synthetic jet actuators; Test case; Uncertainities; Uncertainty quantifications; Uncertainty sources; Actuators; Aerospace engineering; Computational fluid dynamics; Computer simulation; Dynamics; Exhibitions; Size separation; Stochastic models; Turbulence models; Uncertainty analysis
International Standard Book Number (ISBN)
Article - Conference proceedings
© 2012 Hosder, All rights reserved.