% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @ARTICLE{Wenig:894827, author = {Wenig, Philipp J. and Ji, Ruiyun and Kelm, Stephan and Klein, Markus}, title = {{T}owards {U}ncertainty {Q}uantification of {LES} and {URANS} for the {B}uoyancy-{D}riven {M}ixing {P}rocess between {T}wo {M}iscible {F}luids—{D}ifferentially {H}eated {C}avity of {A}spect {R}atio 4}, journal = {Fluids}, volume = {6}, number = {4}, issn = {2311-5521}, address = {Belgrade}, publisher = {MDPI}, reportid = {FZJ-2021-03411}, pages = {161 -}, year = {2021}, abstract = {Numerical simulations are subject to uncertainties due to the imprecise knowledge of physical properties, model parameters, as well as initial and boundary conditions. The assessment of these uncertainties is required for some applications. In the field of Computational Fluid Dynamics (CFD), the reliable prediction of hydrogen distribution and pressure build-up in nuclear reactor containment after a severe reactor accident is a representative application where the assessment of these uncertainties is of essential importance. The inital and boundary conditions that significantly influence the present buoyancy-driven flow are subject to uncertainties. Therefore, the aim is to investigate the propagation of uncertainties in input parameters to the results variables. As a basis for the examination of a representative reactor test containment, the investigations are initially carried out using the Differentially Heated Cavity (DHC) of aspect ratio 4 with Ra=2×109 as a test case from the literature. This allows for gradual method development for guidelines to quantify the uncertainty of natural convection flows in large-scale industrial applications. A dual approach is applied, in which Large Eddy Simulation (LES) is used as reference for the Unsteady Reynolds-Averaged Navier–Stokes (URANS) computations. A methodology for the uncertainty quantification in engineering applications with a preceding mesh convergence study and sensitivity analysis is presented. By taking the LES as a reference, the results indicate that URANS is able to predict the underlying mixing process at Ra=2×109 and the variability of the result variables due to parameter uncertainties}, cin = {IEK-6}, ddc = {530}, cid = {I:(DE-Juel1)IEK-6-20101013}, pnm = {1421 - Design Basis Accidents and Materials Research (POF4-142)}, pid = {G:(DE-HGF)POF4-1421}, typ = {PUB:(DE-HGF)16}, UT = {WOS:000642961700001}, doi = {10.3390/fluids6040161}, url = {https://juser.fz-juelich.de/record/894827}, }