4 Advanced Aerodynamics and Multiphysics
In the field of aerodynamics and modeling for fluid dynamics the
objectives of the CFD Team are 1) the development of reliable,
efficient and accurate predictive CFD softwares for their use in
industrial environment, 2) the numerical investigation of complex flow
physics making use of high-performance computing.
The CFD Team develops physical models to study flow fields in and
around complex geometries. These models must be implemented in
efficient solvers to be tested and used. Two numerical tools are used
and developed at CERFACS for aerodynamics: 1) NSMB has been the main code
for aerodynamics since 1993 and now is the production tool for
Navier-Stokes computations at Airbus France, 2) for the future, a
significant step in code technology has been taken with the
introduction of elsA at CERFACS during last quarter 1999. With
the help of advanced meshing techniques, convergence acceleration
strategies, numerical algorithms and vectorization/parallelism
implementation, NSMB has reached today a sufficient level of
robustness, accuracy and efficiency for steady state aerodynamics
around complex industrial geometries. In particular with the use of
advanced meshing techniques (General Patched Grid, Automatic Mesh
Refinement AMR) developed at CERFACS, structured grids around complex
geometries can be strongly optimized. An engineer has been recruited
in 2001 to improve the integration and versioning processes at CERFACS.
To benefit from new expertise on high-order schemes and turbulence
modelling two new members, proposed by CERFACS, have joined the NSMB
consortium: ENSAM-Paris (2000) and IMF-Toulouse (2001). Nevertheless,
for such large codes as NSMB, the Fortran 77 language suffers from a
lack of readability and of modularity. Amongst other, for this reason,
ONERA and Airbus France have launched the elsA project which
is a CFD code written in C++.
Since 2000 CERFACS has been involved in the development of elsA.
The year 2000 was the beginning of the involvement of CERFACS in the CFD
software platform elsA with just two person working in
elsA. That work was done under a contract between Airbus
France, ONERA and CERFACS dubbed `elsA/NSMB tighthening'. The
aim of that contractual activity was to
-
enable eventually the possibility to swap production
calculations from NSMB to elsA without the usual ``learning
curve'' coming with the use of new software tools. This could be
done by ensuring the commonality of the methods and of their results
in NSMB and in elsA;
- create in the CERFACS an elsA development team with the
NSMB background and experience;
- establish an efficient working relation with the original
elsA developers in ONERA;
- transfer development activities from NSMB to elsA
progressively;
- in the near future, transfer of the applications/modeling
activities from NSMB to elsA.
During that 2000-01 period the elsA team in CERFACS has grown
from two to six people :
-
during the year 2001, two staff members have
joined to help with the development activities on the
elsA/NSMB ``tightening project'':
the adaptation of ONERA's ``Local Multigrid'' (aka
AMR) for Euler flows to 3D turbulent flows
on the one hand, and preliminary
development work on Multigrid on the other hand.
- the transition from development-only team to modeling and new
application has begun:
modification to the turbulent transport equation schemes to ensure
robustness of the Spalart-Almaras model,
turbulence models with the development of the Durbin ( k,
e, v'2 - f ) Model.
One have to point out the structuring effect of the
`NSMB/elsA tightening' contract to the organisation and
methods for collaborative development of CFD codes. For the ease of
complex development at different locations with people from different
organisation, the ONERA/DSNA has setup a web site
http://elsA.onera.fr where information and
documentation is shared.
The willingness of the ONERA and CERFACS to work together has
motivated the signature (march 5, 2001) of an ONERA / CERFACS
cooperation agrement on elsA.
The year 2000 has been a transition year for several reasons:
-
The end of WAVENC (19 Jan.) and MFLAME (15 Mar.) of the FP'4;
- The kick-off of S-WAKE (20 Jan.) and C-WAKE (21 Jan.) of
the FP'5, CERFACS is Work Package manager of all
activities related to numerical simulations and modelling. The
kick-off of OCMATH Regional Program (26 May);
- The launch and development of the hypersonics activity in
close relation with EADS Launch Vehicles and CNES;
- The growing involvement of the team in the elsA
project;
- The arrival of several new researchers in the team related
to the development of these new activities.
- Numerical Aerodynamics
- Wake vortex characterisation of high-lift aircraft (A. Benkenida, G. Jonville,
G. Puigt, D. Darracq)
- Wake vortex dynamics (F. Laporte, H. Moet, D. Darracq)
- Flight Dynamic Coefficients (J. Cormier, S. Champagneux, P. Guillo)
- Turbomachinery Flows (L. Kozuch, R. Struijs, C. Martin, A. Fiala, D. Darracq)
- Propeller aerodynamics (G. Grondin, X. Escrivá, D. Darracq)
- Axial fan optimization (C. Martin, B. Marquez)
- Numerical Simulations of Crosswind Inlet Flows at Low Mach Numbers (S. Champagneux)
- Numerical Methods and Software Engineering
- Finite Element Method in Unstructured Meshes (G. Chevalier, F. Ducros, B. Marquez)
- Meshing techniques (J. Bohbot, J.-Ch. Jouhaud, M. Montagnac, D. Darracq)
- Spalart-Allmaras (H. Pascal-Jenny)
- MAEVA (H. Pascal-Jenny)
- Development and implementation of a wake vortex model in
flight simulators (H. Moet, G. Grondin, D. Darracq)
- Software engineering (J. Bohbot, S. Champagneux, J.-Ch. Jouhaud,
Ph. Piras)
- Object Oriented CFD with elsA (M. Montagnac, G. Chevalier, S. Champagneux,
J.-Ch. Jouhaud)
- CFD Team Support (S. Champagneux, M. Labadens, F. Dabireau, V. Roche)
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