Robust performance assessment for an oscillating airfoil combining the time spectral method and a semi-intrusive uncertainty propagation approach

The power extracted from a flowing fluid by an oscillating airfoil in a combined heaving and pitching motion is analyzed with fluctuations of the heaving amplitude taken into account. The uncertainties on the airfoil motion are propagated throughout the ALE artificial compressibility solver using an original semi-intrusive (SI) method which can be applied to uncertainties described by any type of probability density function.The computational cost is reduced thanks to an implicit time spectral (TSM) method. The TSM/SI strategy is compared, in terms of accuracy and robustness, with a more conventional dual-time-step/non-intrusive polynomial chaos approach.