On the influence of uncertainty in computational simulations of a high-speed jet flow from an aircraft exhaust
Résumé
A classic approach to computational fluid dynamics is to perform simulations with a fixed set of variables in order to account for parameters and boundary conditions. However, experiments and real-life performance are subject to exhibit variability in these conditions. In recent years, the interest of undertaking simulations under uncertainty is increasing, but this is not yet a common rule, and simulations with lack of information are still taking place. This procedure could be missing details such as whether sources of uncertainty a_ect dramatic parts in the simulation of the flow. One of the reasons of avoiding to quantify uncertainties is that they usually require to run an una_ordable number of CFD simulations to develop the study. To face this problem, Non-Intrusive Uncertainty Quantification (UQ) has been applied to 3D Reynolds-Averaged Navier-Stokes simulations of an under-expanded jet from an aircraft exhaust with the Spalart-Allmaras turbulent model, in order to assess the impact of inaccuracies and quality in the simulation. To save a large number of computations, sparse grids are used to compute the integrals and built surrogates for UQ. Results show that some regions of the jet plume can be more sensitive than others to both physical and turbulence model variance. The Spalart-Allmaras turbulent model is demonstrated to have an accurate performance with respect to other turbulent models in RANS, LES and experimental data, and the contribution of a large variance in its parameter is analysed. With these outputs, this work aims to point out the relevance in the visualisation of stochastic jet flow simulations when adding uncertainty sources that are present in the jet performance and computational modelling.
Domaines
Modélisation et simulation
Origine : Fichiers produits par l'(les) auteur(s)
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