M/F researcher "Numerical Methods and Anisotropic Mesh Adaptation for RANS and LES Simulations"

Job Description

Missions

The candidate's mission will be to gain a deeper understanding of the interactions between numerical methods, anisotropic mesh adaptation, and turbulence modeling, with the aim of developing a robust and accurate simulation framework for RANS and LES calculations in YALES2.
The work will combine the analysis of limitations currently observed on highly anisotropic meshes with the development of new numerical approaches to fully exploit their potential. Particular attention will be paid to the effective accuracy of discretization schemes on anisotropic meshes, the consistency of pressure–velocity coupling, the conservation of quantities during remeshing operations, and the robustness of the RANS solver.
The project will also investigate the influence of the order of numerical schemes on the optimal mesh metric, as well as the determination of appropriate time steps when semi-implicit time-integration strategies are used. The ultimate goal is to establish design principles ensuring an optimal match between numerical methods, mesh resolution, and turbulence modeling, in order to maximize simulation accuracy for a given computational cost.

Activity

• Analyze the performance and limitations of current numerical methods on anisotropic meshes for RANS and LES simulations.
• Develop, implement, and validate new numerical approaches within the YALES2 code.
• Investigate the influence of mesh anisotropy and numerical scheme order on simulation accuracy.
• Improve the robustness of pressure–velocity coupling and incompressible flow solvers.
• Develop conservative remeshing and interpolation strategies.
• Assess the consistency between numerical methods, mesh metrics, and turbulence models on academic and industrial test cases.
• Perform large-scale simulations using high-performance computing facilities.
• Disseminate research results through peer-reviewed publications and presentations at international conferences.

Your Profil

Skills

Expected skills :
• Strong background in computational fluid dynamics.
• Knowledge of RANS and/or LES methodologies.
• Scientific programming
• Interest in advanced numerical methods and high-performance computing.
• Ability to work in a collaborative international research environment.
Desired experience :
• Experience in computational fluid dynamics.
• Experience in numerical methods development and/or turbulence modeling.
• Experience with high-performance computing is an asset.
Required degree :
• PhD in Fluid Mechanics, Physics, Applied Mathematics, Scientific Computing, or a related field.
Application package :
• A detailed curriculum vitae and a letter of motivation.

Your Work Environment

Joint Research Unit (UMR 5519) of the Centre National de la Recherche Scientifique (CNRS), the Institut National Polytechnique de Grenoble (Grenoble INP) and the University Grenoble-Alpes (UGA). LEGI carries out a wide range of research activities with a common ground: fluid mechanics and related transport phenomena.
Scientific Background :
The relevance of numerical simulations of turbulent flows relies on achieving an optimal balance between accuracy and computational cost. Reynolds-Averaged Navier–Stokes (RANS) and Large-Eddy Simulation (LES) approaches provide different levels of fidelity at computational costs suited to a wide range of applications. Beyond turbulence modeling itself, their accuracy and efficiency depend strongly on the numerical methods employed and on the quality and suitability of the computational mesh.
For several years, the MOST team (Modeling and Simulation of Turbulence) at LEGI has been developing automatic mesh adaptation strategies for DNS, LES, and RANS simulations within the YALES2 code. These approaches are based on physically motivated criteria to ensure that the mesh is consistent with the requirements of the selected turbulence modeling approach.
Recent results have demonstrated the potential of this methodology to optimize meshes and reduce the dependence of simulation results on user choices made during mesh generation. However, several scientific and numerical challenges remain open regarding the interaction between numerical methods and meshes: effective accuracy of numerical schemes on highly anisotropic meshes (including high-order methods), preprocessing of mesh metrics (e.g., mesh gradation) to satisfy numerical constraints, robustness of pressure–velocity coupling for incompressible flows, conservation of physical quantities during remeshing and interpolation operations, and more.
The recruited person will be assigned to the MOST team. The research activities of the MOST (Modelling and Simulation of Turbulence) team focus on the numerical prediction of turbulent and multiphase flows with a broad range of objectives from fundamental understanding of flow properties to technologies optimization. The research team has the ambition to address all the needed scientific fields to understand turbulent and multiphase flows from simulation: numerical methods, turbulence models, physics of fluids, flow control...
The main objective is to develop numerical tools to efficiently predict and to deeply understand flows in more and more physically and geometrically complex configurations. This activity is inherently multidisciplinary with strong collaborations with other scientific fields, as applied mathematics or statistical physics. Fluid mechanics is ubiquitous in geophysical and industrial applications. Better understanding of flows will help to address major challenges to deal with new energy and environmental constraints. Collaborations with experts in geosciences and in renewable energy development have been set-up to respond to these societal issues.
Scientific supervisor : Manuel Bernard - MOST team

Constraints and risks

No risk identified.

Compensation and benefits

Compensation

between 3041,58€ and 4216,70€ gross monthly depending on experience

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions