Overview Over Some Uncertainty Quantification (UQ) Activities in Hypersonics
Speaker: Pietro Marco Congedo, INRIA Bordeaux Sud-Ouest, Talence Cedex, France
Presentation
Abstract
Simulation of aerospace applications, such as atmospheric entries of spacecraft, are challenging problems involving many complex physical phenomena, including rarefied gas effects, aerothermochemistry, radiation, and the response of thermal protection materials to extreme conditions. Reliable predictions require sophisticated physico-chemical models as well as a systematic and comprehensive treatment of model calibration and validation, including the quantification of the uncertainties inherent in such models. It still remains very challenging to establish “error prediction” on the numerical results that account for all uncertainties and errors in order to make sound decisions. This talk is focused on some activities about the application of uncertainty quantification techniques to hypersonic flows in the context of a long-term collaboration between INRIA and von Karman Institute (VKI). The first study is oriented towards the characterization of physical and model uncertainties in two VKI facilities: i) the characterization of the free stream conditions in the VKI Longshot facility, ii) the Uncertainty Analysis of Carbon Ablation in the VKI Plasmatron. Secondly, a sensitivity study over the interactions between the chemical reactions and their influence on the error of the radiative heat flux is presented. In this case, quantifying uncertainties in the chemical mechanisms is necessary for an accurate heat-flux prediction, even if the dimensionality of the stochastic space can increase tremendously. Finally, a new methodology to rebuild freestream conditions for the trajectory of a reentry vehicle from stagnation-point measurements is presented, where uncertainties due to measurements and model parameters are taken into account.
Biography
Pietro Marco Congedo is a Research Scientist at INRIA Bordeaux and team Leader of AQUARIUS (Joint Team from INRIA and Stanford University). This team is focused on the development of uncertainty quantification techniques for CFD problems. He graduated with honours in Materials Engineering at University of Lecce (Italy). After his Master in Fluid Mechanics at Arts et Métiers (Paris, France), he received his Ph.D. in Energy Systems at University of Lecce in 2007. His research interests are in the numerical simulation and optimisation of real gas flows, uncertainty quantification, thermodynamics of complex flows and multiphase flows.