Uncertainty quantification (UQ) aims at a meaningful characterization of uncertainties in stochastic
systems and efficient propagation of these uncertainties for quantitative validation of model
predictions from available measurements. In this paper, UQ of flows around cylinder is studied by
non-intrusive polynomial chaos (NIPC) method. Based on the validation with benchmark results, discussions are mainly focused on the statistic
properties of horizontal and vertical components of the total force on the cylinder. The influence of
random variables on flow parameters decreases with increasing of viscosity coefficient. The results
indicate the effect of NIPC method on the simulation of propagation of uncertainty in the flow field.