Uncertainty quantification and sensitivity analysis of the SST turbulence model applied to VIV

Abstract

This paper presents the results of an Uncertainty Quantification and Sensitivity Analysis carried out for the $k-\omega$ SST turbulence model applied to the bi-dimensional study of Vortex Induced Vibrations of an elastically mounted cylinder. The turbulence model parameters are treated as epistemic uncertain variables and the forward propagation of uncertainty is evaluated using stochastic expansions based on non-intrusive polynomial chaos. The relative contribution of the closure coefficients to the total uncertainty of the output quantities of interest, the non-dimensional amplitude and the frequency ratio, is evaluated using the Sobol indices. The analysis is repeated for different orders of the polynomial chaos expansion. A set of significant coefficients, which contribute most to the uncertainty for this specific case is identified, and furthermore compared with the sets provided for some other selected flow problems in order to gain further insight on the $k-\omega$ SST turbulence model.