Furthermore, our results also indicate that the crucial aspect when obtaining accurate inner-scaled velocity measurements is the wind-tunnel flow quality, which is more critical than the accuracy in wall-shear stress measurements. In the present analysis we account for these correlations, which may lead to a lower overall uncertainty estimate due to error cancellation. Note that in most studies of wall-bounded turbulence the correlations among parameters are not considered, and the uncertainties from the various parameters are directly added when determining the overall uncertainty of the measured quantity. Note that these values are lower than the ones reported in other wall-bounded turbulence studies. The relative errors in wall-shear stress, friction velocity and viscous length are 0:44%, 0:23% and 0:22%, respectively. ![]() Moreover, global sensitivity analyses with Sobol indices showed that the HWA measurements are most sensitive to the wire voltage, and in the case of OFI the most sensitive factor is the calculation of fringe velocity. In flow velocity measurements with HWA, the results indicate that the estimated uncertainty is lower when the correlations among parameters are considered, than when they are not taken into account. In the forward problem, very small differences were found when using Monte Carlo (MC), Polynomial Chaos Expansion (PCE) and linear perturbation methods. The correlations between the parameters are taken into account through the Bayesian inference with error-in-variable (EiV) model. Problems, so that the contributions to the overall uncertainty of the measured quantities can be evaluated. Both statistical and classical methods are used for the forward and inverse In this study, the sources of uncertainty of hot-wire anemometry (HWA) and oil-ifilm interferometry (OFI) measurements are assessed. The relative errors in wall-shear stress, friction velocity and viscous length are 0.44%, 0.23% and 0.22%, respectively. ![]() ![]() Both statistical and classical methods are used for the forward and inverse problems, so that the contributions to the overall uncertainty of the measured quantities can be evaluated. ![]() In this study, the sources of uncertainty of hot-wire anemometry (HWA) and oil-film interferometry (OFI) measurements are assessed.
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