Aerodynamics and Energetics Modeling

Turbulence Modeling

Calculation of 3D flow with separation
around the OAT15A airfoil in the T2 transonic wind tunnel
(M = 0.754, = 1.15 deg., Re = 3.5x10 6 )
- High-resolution image: 48 Kb

The turbulence modeling activity includes four areas:

• Analysis of model behaviours for various practical configurations (boundary layer on a wing or fuselage, separated flows, wakes, etc.) to identify their strengths and weaknesses and how they can be improved.
• Creation of experimental databases using DMAE's own research facilities (research wind tunnels, THALES water tunnel) as well as the Fauga-Mauzac F2 wind tunnel and the other wind tunnels of Onera (DAFE, GMT, etc.) to validate the models.
• Development of new models better describing the physics, based on available mathematical tools and the constraints determined from the physical phenomena observed. Another major requirement for the models is numerical stability. Finally, the complexity and cost of the models varies depending on the applications. The models are first tested at DMAE in simple configurations.
• Inclusion of these models in Onera's major codes to study their performance in complex situations and ensure their dissemination to the other departments of Onera and the aeronautical industry. Systematic use of the models included in the major codes is made by other departments of Onera conducting applied research (DAAP, DEFA, etc.).

A major asset of DMAE is to have researchers active in one or more of these fields working together.

The demand in the aerospace industry is on improved predictions of separated flows, vortical flows, jets and mixing layers, unsteady flows, thermal turbulence and compressible turbulence. DMAE develops and improves models to treat these applications. Another field of DMAE expertise is flows over rough surfaces.

The present trend is to no longer use eddy viscosity models, which linearly relate the turbulent stresses to the mean rate of strain and are not well suited for complex flows, and to favour non-linear models as well as differential Reynolds stress models.

DMAE benefits from good relations with industry and the teams working on turbulence modeling in France, Europe (via ERCOFTAC and EC projects), the U.S. (NASA, universities), Russia (ITAM) and Israel (Technion).

Last Update: 9 May 2006 - © ONERA 2009 - Terms of use