Wall-bounded turbulent flows occur in many engineering appl ications. The quantities of interest (QoIs) of these flows can be accura tely obtained through experimental measurements and scale-resolving nume rical approaches\, such as large eddy simulation (LES). However\, due to the prohibitive computational costs imposed by the turbulent boundary l ayers (TBL) involved in these flows\, the use of a standard wall-resolvi ng (WR)LES is limited to low Reynolds (Re-) numbers. As an alternative\, wall-modeled (WM)LES can be employed\, in which the near-wall region of the TBL is modeled.

\n\nThis thesis evaluates the uncertainties i nvolved in the measured QoIs of a set of experiments on TBLs\, and also\ , investigates the predictive accuracy and sensitivity of LES\, both wal l-resolving and wall-modeled. For these purposes\, different uncertainty quantification (UQ) techniques are employed.

\n\nIn particular\, such techniques are applied to the forward (uncertainty propagation) and inverse (parameter estimation) problems involved in the measurement of mean velocity and wall shear stress using hot-wire anemometry and oil-fi lm interferometry\, respectively. The possibility of reducing epistemic uncertainties by a more detailed analysis is demonstrated. The metamodel s constructed by combining non-intrusive generalized polynomial chaos ex pansion with the stochastic-collocation method are employed to investiga te the sensitivity of WRLES of turbulent channel flow to grid resolution . This research further provides a set of recommendations for grid resol ution. Through the use of a systematic simulation campaign\, the predict ive accuracy and sensitivity of WMLES of the same flow is investigated w ith respect to several influential factors. The metamodel technique is a lso used to explore the sensitivity to the grid anisotropy and wall mode l parameters. Based on this study\, a set of best practice guidelines is obtained for WMLES of turbulent channel flow\, the validity of which is confirmed in a wide range of Re-numbers. For all the UQ-based studies\, variance-based sensitivity analysis is also performed.

\n\nFor WM LES\, this thesis also introduces several developments in wall-stress mo deling. The performance of algebraic wall-stress models is investigated in an a-priori framework\, using accurate WRLES data. Two novel approach es based on integrating the wall model and dynamically adjusting its par ameters are proposed and tested. This thesis also contributes to the dev elopment of an open-source library for WMLES based on OpenFOAM\, which i s used in the afore-mentioned systematic study for channel flow.

\n DESCRIPTION:Disputation SUMMARY:Application of Uncertainty Quantification Techniques to Studies o f Wall-Bounded Turbulent Flows LOCATION:2446\, ITC\, Lägerhyddsvägen 2\, hus 2\, Uppsala TZID:Europe/Stockholm DTSTART:20181123T101500 DTEND:20181123T235900 UID:20181123T101500-39468@uu.se END:VEVENT END:VCALENDAR