Chapter 1  Introduction

• Aerodynamics (supervision: G. Chevalier). Developing advanced simulation codes for aerodynamics applications in Europe is now the central theme of this group. The code NSMB which had been the center of developments at CERFACS until 2000 and was the production code of Airbus Toulouse has been progressively replaced in 2002 by the new software elsA developed by ONERA with a strong participation of CERFACS. In 2003, NSMB has been completely stopped at CERFACS and all efforts focus now on elsA and its future developments.
• Combustion. The LES (Large Eddy Simulation) tool of CERFACS (AVBP) has become the standard tool for LES of reacting flows at many places in Europe (CNRS laboratories, ONERA centers, Universities in Spain or Germany, etc). Another important change took place: Institut Français du Pétrole is now developing AVBP jointly with CERFACS. Industrial partners (SNECMA, Turbomeca, Siemens, Alstom) have continued their collaboration with CERFACS to increase AVBP capabilities and validate it in multiple cases. In certain cases, the industrial use of LES has already been tested (at SNECMA or TURBOMECA) opening a new area for reacting flow computations in industry.

• Even though code developments are an important part of the team work, the core of this activity remains research in fluid mechanics as evidenced by the number of publications (which has increased in 2003) and by the reputation of the team. Obviously, the focus of this academic work has shifted from fundamentals studies in turbulence or in laminar flames towards more complex topics: unsteady flows, fluid structure interaction, coupled phenomena, optimization, acoustic / combustion instabilities, two-phase reacting flows. This academic level is one of the keys explaining the present results of the CFD team. It also explains why outside experts join CERFACS as consultants to be able to find codes in which they can test new concepts: Pr Nicoud (Montpellier) or Pr Sagaut (Paris VI) for example are now collaborating routinely to CERFACS work. The quality of the research produced by CERFACS was also recognized in 2003 through the Grand Prix de l'Académie des Sciences for T. Poinsot, jointly with D. Veynante, and the PhD prize in aerodynamics of Académie des Sciences, Belles Lettres et Inscriptions de Toulouse for Dr F. Laporte.
• A significant part of the activity of the CFD team continues to be supported by European contracts. The 5th PCRD contracts on wake vortices (C Wake, S Wake, Wakenet 2, Awiator), LES of combustion in gas turbines (Icleac, Preccinsta, Molecules, Fuelchief, Desire), atmospheric pollution (Stopp) are being continued and expanded through 6th PCRD programmes (Fluistcom, Timecop, Lessco2) confirming the efficiency of the team at the European level.
  
  
• The team gathers now more than 40 people but less than 10 of these are at CERFACS on a permanent basis. All others spend 2 to 3 years at CERFACS and leave so that CERFACS continues to provide multiple high-level experts for industry: EADS in Paris, CORYS in Grenoble, Siemens in Regensburg, Airbus-F, Airbus-D and CEA.
  
  
• The new topics started in 2000 or 2001 (such as two-phase flows or aerodyamics with elsA) have expanded very rapidly: 7 scientists are now working full time on two phase flow (supervision: Dr Cuenot) and more than 10 are working on elsA. Such rapid evolutions require a high level of adaptability from the whole team. In 2003, other new topics have also appeared such as fluid structure interaction with combustion, optimization for reacting flows, aircraft impact on environment (supervision: D. Cariolle) suggesting that the team will adjust again in the near future.
  
  
• The collaboration with laboratories keeps increasing. In the field of combustion, AVBP is now used in France at IMF Toulouse, Ecole Centrale Paris, IRPHE, ONERA Paris, ONERA Toulouse and Institut Français du Pétrole. Multiple joint papers have been written with foreign universities (Netherlands, Germany) where experiments are performed and for which CERFACS performs LES. This collaborative European work is typical of the present research of the team. The CRCT (`Centre de Recherche sur la Combustion Turbulente') is very active: annual CRCT meetings gather more than 40 scientists. Outside Europe, CERFACS continues to collaborate with the Center of Turbulence Research: 4 CERFACS scientists participated to the CTR Summer Program in 2002 and one of our scientist is presently at Stanford for a year before coming back to CERFACS to work on aircraft impact in 2004.
• Formation is still an important part of the team's activity: in 2002 and 2003, 15 trainees will have spent periods of six months at CERFACS to learn CFD. The PhD program is also increasing with 17 PhD students working in the team in 2003. Formation also takes other forms: in the case of industry, CERFACS has received trainees working for industry (SNECMA), for laboratories (IRPHE, Ecole Centrale de Paris, Ecole des Mines d'Albi) for periods of one to four weeks to teach them how to use CERFACS codes. Another ambitious project was started by sending a senior of the team for six months in 2003 to Turbomeca in Pau. Here formation worked both ways: he has shown the use of AVBP to Turbomeca and has learned the basis of the work of helicopter gas turbine designers. Recently, CERFACS has participated to the training of Airbus users of elsA with ONERA.