Team Bacchus

Overall Objectives
Scientific Foundations
Application Domains
New Results
Contracts and Grants with Industry
Other Grants and Activities

Section: Other Grants and Activities

Actions Funded by the EC

ADIGMA: a European project on the development of adaptive higher order variational methods for aerospace applications

Participants : Rémi Abgrall [ Corresponding member ] , Pascal Hénon, Pascal Jacq, Cédric Lachat, Adam Larat, François Pellegrini, Mario Ricchiuto.

Grant: European Commission

Dates: 2006-2009

Partners: AIRBUS F et AIRBUS D, DASSAULT, ALENIA, DLR, ONERA, NLR, ARA, VKI, INRIA, Nanjing University, Universities of Stuttgart, Bergame, Twente, Nottingham, Swansea, Charles (Prague), Varsovie, CENAERO, ENSAM Paris )

Overview: Computational Fluid Dynamics is a key enabler for meeting the strategic goals of future air transportation. However, the limitations of today numerical tools reduce the scope of innovation in aircraft development, keeping aircraft design at a conservative level. Within the 3rd Call of the 6th European Research Framework Programme, the strategic target research project ADIGMA has been initiated. The goal of ADIGMA is the development and utilization of innovative adaptive higher-order methods for the compressible flow equations enabling reliable, mesh independent numerical solutions for large-scale aerodynamic applications in aircraft design. A critical assessment of the newly developed methods for industrial aerodynamic applications will allow the identification of the best numerical strategies for integration as major building blocks for the next generation of industrial flow solvers. In order to meet the ambitious objectives, a partnership of 22 organizations from universities, research organizations and aerospace industry from 10 countries with well proven expertise in CFD has been set up guaranteeing high level research work with a clear path to industrial exploitation.


ADDECCO : ADaptive schemes for DEterministic and stoChastiC Flow PrOblems

Participant : Rémi Abgrall [ Corresponding member ] .

Grant: European Commission

Dates: 2009-2014

The numerical simulation of complex compressible flow problem is still a challenge nowadays, even for the simplest physical model such as the Euler and Navier Stokes equations for perfect gases. Researchers in scientific computing need to understand how to obtain efficient, stable, very accurate schemes on complex 3D geometries that are easy to code and to maintain, with good scalability on massively parallel machines. Many people work on these topics, but our opinion is that new challenges have to be tackled in order to combine the outcomes of several branches of scientific computing to get simpler algorithms of better quality without sacrificing their efficiency properties. In this proposal, we will tackle several hard points to overcome for the success of this program.

We first consider the problem of how to design methods that can handle easily mesh refinement, in particular near the boundary, the locations where the most interesting engineering quantities have to be evaluated. CAD tools enable to describe the geometry, then a mesh is generated which itself is used by a numerical scheme. Hence, any mesh refinement process is not directly connected with the CAD. This situation prevents the spread of mesh adaptation techniques in industry and we propose a method to overcome this even for steep problems.

Second, we consider the problem of handling the extremely complex patterns that occur in a flow because of boundary layers: it is not always sufficient to only increase the number of degrees of freedom or the formal accuracy of the scheme. We propose to overcome this with class of very high order numerical schemes that can utilise solution dependant basis functions.

Our third item is about handling unsteady uncertainties in the model, for example in the geometry or the boundary conditions. This need to be done efficiently: the amount of computation increases a priori linearly with the number of uncertain parameters. We propose a non–intrusive method that is able to deal with general probability density functions (pdf), and also able to handle pdfs that may evolve during the simulation via a stochastic optimisation algorithm, for example. This will be combined with the first two items of this proposal. Many random variables may be needed, the curse of dimensionality will be dealt thanks to multiresolution method combined with sparse grid methods.

The aim of this proposal is to design, develop and evaluate solutions to each of these challenges. Currently, and up to our knowledge, none of these problems have been dealt with for compressible flows with steep patterns as in many moderns aerodynamics industrial problems. We propose a work program that will lead to significant breakthroughs for flow simulations with a clear impact on numerical schemes and industrial applications. Our solutions, though developed and evaluated on flow problems, have a wider potential and could be considered for any physical problem that are essentially hyperbolic.


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