CENTRALE LYON - Postdoctoral position - Dynamic calibration of turbulence models

ECL and Laboratory presentation

Founded in 1857, École Centrale de Lyon is one of the top 10 engineering schools in France. It trains more than 3,000 students of 50 different nationalities on its campuses in Écully and Saint-Étienne (ENISE, in-house school): general engineers, specialized engineers, masters and doctoral students. With the Groupe des Écoles Centrale, it has three international locations. The training provided benefits from the excellence of the research carried out in the 6 CNRS-accredited laboratories on its campuses, the 2 international laboratories, the 6 international research networks and the 10 joint laboratories with companies. Its excellent research and high-level teaching have enabled it to establish double degree agreements with prestigious universities and advanced partnerships with numerous companies. With its focus on sobriety, energy, the environment and decarbonization, Centrale Lyon intends to respond to the problems faced by socio-economic players in the major transitions.

The Fluid Mechanics and Acoustics Laboratory (Laboratoire de Mécanique des Fluides et d'Acoustique - LMFA) develops a continuum of research in fluid mechanics and acoustics, from the understanding and the modelling of physical phenomena to applied research, in collaboration with industrial partners and public institutions. Research is organized around three major socio-economic fields: aeronautics and transport, environment and risks, and energy and processes for industry and life.

Research field presentation :

The Lattice Boltzmann method (LBM) is gaining increasing interest in Computational Fluid Dynamics. While traditional methods rely on a discretization of the Navier-Stokes equations at a macroscopic level, the LB method considers the fluid at a kinetic level. Capturing the dynamics of collections of fluid particles distributed over a lattice is here preferred to solving non-linear PDEs. Processing a simulation in this way has some advantages. The low numerical dissipation allows for accurate simulation of time-dependent flows, enabling sensitive applications such as aeroacoustics. Furthermore, the high scalability on massively parallel computers can lead to advantageous turn-around times for industrial applications.

The Laboratory of Fluid Mechanics and Acoustics (LMFA, CNRS, Ecole Centrale de Lyon) is seeking a highly qualified candidate for a post-doctoral research fellowship regarding the dynamic calibration of turbulence models.

Description of the activities
The successful candidate will be in charge of improving the turbulence model used in the ProLB software developed at LMFA with other academic and industrial partners. The shear-improved Smagorinsky model is employed for large-eddy simulation of wall-bounded turbulent flows. The current implementation requires the definition of a cut-off frequency that should represent a characteristic frequency of the simulated flow. The main focus will be to propose a self-adjustement of this frequency.

This research activity is part of a 3 years-long major project co-funded by the DGAC (French Civil Aviation) and directed by Airbus. The successful candidate will therefore develop his research activity collaboratively with the other academic and industrial partners of the project.

Scientific references:

[1] E. Lévêque, et al.  “Shear-improved Smagorinsky model for large-eddy simulation of wall-bounded turbulent flows”, Journal of Fluid Mechanics , Volume 570 , 10 January 2007 , pp. 491 – 502, doi:10.1017/S0022112006003429

[2] A. Cahuzac, et al.  “Smoothing algorithms for mean-flow extraction in large-eddy simulation of complex turbulent flows”, Physics of Fluids 1 December 2010; 22 (12): 125104, doi:10.1063/1.3490063

[3] J. Boudet, et al. “Unsteady Lattice Boltzmann Simulations of Corner Separation in a Compressor Cascade”, Journal of Turbomachinery, vol. 144, no 1, January 2022, doi: 10.1115/1.4052017.

Diplomas : PhD in Engineering, Physics, Theoretical and Applied Mechanics, or Applied Mathematics

Experience : None

Knowledge required: Contributions in the area of scientific computing and Computational Fluid Dynamics. Prior Experience in turbulence modelling, machine learning or the Lattice Boltzmann method is an advantage.

Operational skills : Physical analysis of fluid dynamics, advanced skills in programming and numerical methods, writing scientific reports and articles, presenting at scientific conferences.

Behavioural skills : Independence, ability to work in a team and adapt to the needs of colleagues, creativity

Work context / environment_______________________________

Attendance at an European  scientific conference is expected.

Recruitment process_______________________________

The recruitment process takes place in two stages, supervised by a recruitment committee, in accordance with Centrale Lyon's OTMR policy.

• Study of the written application:  CV with a cover letter, a summary of recent work and interests,

                one or two letters of reference

• Selection interview: in person or by videoconference

Recruitment timetable: 3 weeks

Selection criteria : excellence