%0 Journal Article
%A Han, Daoru
%A Hosder, Serhat
%D 2014
%I Begell House
%K uncertainty quantification, polynomial chaos, stochastic response surface, computational fluid dynamics, synthetic jet actuators
%N 6
%P 511-533
%R 10.1615/Int.J.UncertaintyQuantification.2014010659
%T INHERENT AND EPISTEMIC UNCERTAINTY ANALYSIS FOR COMPUTATIONAL FLUID DYNAMICS SIMULATIONS OF SYNTHETIC JET ACTUATORS
%U http://dl.begellhouse.com/journals/52034eb04b657aea,21fe10c229b8ad74,6bb6afa40546e05d.html
%V 4
%X A mixed uncertainty quantification method was applied to computational fluid dynamics (CFD) modeling of a synthetic
jet actuator. A test case, flow over a hump model with synthetic jet actuators, was selected from the CFDVAL2004
workshop to apply the second-order probability framework implemented with a stochastic response surface obtained from quadrature-based nonintrusive polynomial chaos. Three uncertainty sources were considered: (1) epistemic uncertainty in turbulence model, (2) inherent uncertainty in free stream velocity, and (3) inherent uncertainty
in actuation frequency. Uncertainties in both long-time averaged and phase averaged quantities were quantified using a fourth-order polynomial chaos expansion. 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 coefficients at three selected locations. The mixed uncertainty results for phase-averaged x-velocity distributions at three selected locations showed that the 95% confidence interval could
generally envelop the experimental data. The Sobol indices showed that near the wall, the uncertainty in turbulence
model had a main influence on the x-velocity. While approaching the main stream, the uncertainty in free stream velocity became a larger contributor. The mixed uncertainty quantification approach demonstrated in this study can also be applied to other CFD problems with inherent and epistemic uncertainties.
%8 2014-10-17