Wednesday, June 17, 2020

UQSay #11

The eleventh UQSay seminar on Uncertainty Quantification and related topics, organized by L2S, MSSMAT, and EDF R&D, will take place online on Thursday afternoon, June 25, 2020.

14h–15h — Guilhem Lavabre (EM2C) — [slides]

Dimension reduction and surrogate-modelling for uncertain auto-igniting flame simulations

Numerical simulations have become a backbone of research and industrial design, but few are as expensive as high-fidelity combustion simulations. These combine unsteady turbulent flow and chemistry computations, meaning a few tens of transport equations on meshes of several million nodes. As a result, such simulations can cost up to several millions of CPU-hours.

Alas, all this computational complexity does not shield the results from uncertainty as many sources of variability remain. To name a few: model calibration, operating conditions, exact composition of complex fuels, geometric variability of combustion chambers…

In this context, very sample-efficient methods are needed to make uncertainty propagation even affordable.

This presentation will focus on proposing methods to propagate chemical and experimental uncertainties in simulations of an auto-igniting flame. A toy-problem subject to similar physical phenomena will be introduced. It will be used to implement some uncertain dimension reduction methods. Different surrogate modelling approaches will then be tested and compared to put forward an affordable and relevant design of experiment for this problem.

Joint work with Olivier Gicquel and Ronan Vicquelin.

PDF abstract with illustrations: uqsay11_abstract_glavabre.pdf.

Organizers: Julien Bect (L2S), Emmanuel Vazquez (L2S), Didier Clouteau (MSSMAT), Filippo Gatti (MSSMAT), Fernando Lopez Caballero (MSSMAT), Bertrand Iooss (EDF R&D).

Practical details: the seminar will be held online using Microsoft Teams.

If you want to attend this seminar (or any of the forthcoming online UQSay seminars), and if you do not already have access to the UQSay channel on Teams, simply send an email and you will be invited. You will find the link to the seminar on this channel, approximately 15 minutes before the beginning.

The technical side of things: you can use Teams either directly from you web browser or using the "fat client", which is available for most platforms (Windows, Linux, Mac, Android & iOS). We strongly recommend the latter option whenever possible. Please give it a try before the seminar to anticipate potential problems.