Offres de Thèses et Postdocs

We have funding for a Ph.D. position on fundamental turbulence modeling. The student will work in collaboration with the two advisors A. Alexakis in LPENS at École Normale Supérieure Paris, and S. Chibbaro LISN at Université Paris-Saclay. The goal of the Ph.D. would be to build and test a novel stochastic models using large-scale direct numerical simulations and machine learning. The potential candidate should have some familiarity with numerics, and motivation to study turbulent flows. For further information please see https://www.phys.ens.fr/~alexakis/StochasticModeling.html or contact us directly by email.

Toutes les informations sur cette annonce de postdoc sont accessibles sur le portail du CNRS:https://emploi.cnrs.fr/Gestion/Offre/Default.aspx?Ref=UMR7648-SEBGAL-001

The postdoc project involves developing and using the Wave Turbulence approach for describing random nonlinear waves in geophysical situations: internal and inertial waves in the ocean and atmosphere, water surface waves, planetary Rossby waves. The project includes advancing and validating the theoretical approach using the numerical simulations of the wave kinetic equations and comparing them with simulations of the dynamical fluid models, laboratory experiments and field observations. Applications to describing the ocean mixing and other transport phenomena important for weather and climate modeling will be considered.

Within the ANR MUFDD project, a major challenge is to account for the strong complexity and variability of urban flows due to the change in atmospheric stability. Urban flows are known to be highly complex and to have a high variability. These limitations are exacerbated when buoyancy effects are taken into account and added to wind-shear effects. Deriving reduced-order models which are versatile and robust with respect to a change in boundary conditions such as wind speed or atmospheric stability remains crucial.The main objective of the position opening at LHEEA is to build upon previous work conducted by the DAUC group on the dynamics of isothermal street canyon flows to investigate the influence of buoyancy on the spatio-temporal characteristics of street canyon flows via a series of detailed wind-tunnel experiments. Attention will be devoted to the dynamics of the coherent structures within and above the canyon, and to their interaction with those of the oncoming boundary layer.

The main objective of this project is to further develop a new methodology to generate inflow conditions for aerodynamics and aeroelastic codes for floating offshore wind turbines operating in the wake of an upstream wind turbine. Accounting for the correct characteristics of the oncoming wind is crucial for the accuracy of aeroelastic simulations.Promising results have been obtained in previous work (https://doi.org/10.5194/wes-8-1711-2023), based on directly coupling wind tunnel experiments to an aeroelastic code. The goal of the opening position is to further improve this approach, in particular by assessing the potential of using high-speed stereoscopic PIV, as well as investigating the degree of representativity of the generated inflow conditions required to perform satisfactory aeroelastic simulations.

The post-doc will carry out numerical simulations of the flow around a free-moving gondola. These simulations will enable a very detailed study of the phenomena involved in pendulum dynamics. These studies are part of the ANR TURB-Cab project.

L’équipe Curiosity de l’institut Pprime souhaite recruter un.e doctorant.e (ou un.e post-doctorant.e) dans le cadre d’une collaboration avec les Voies Navigables de France (VNF) et le Laboratoire de Mathématiques et Applications (LMA) de Poitiers afin d’étudier la navigation en milieu confiné dans une optique d’interaction fluide-structures. En complément à un post-doctorat en cours sur une revisite des travaux théoriques sur les effets de confinement hydraulique et ondulatoire pour un bateau fluvial en interaction avec l’ouvrage (typiquement un canal à forme trapézoïdal), nous souhaitons désormais alimenter les études théoriques par des expériences permettant de cribler les modèles ainsi que de guider les modélisateurs vers les modèles pertinents du fait de lacunes dans la compréhension des phénomènes tels que révélées par l’analyse de la littérature et que les expériences pourraient combler.

L’équipe Curiosity de l’institut Pprime souhaite recruter un.e post-doctorant.e dans le cadre d’une collaboration avec les Voies Navigables de France (VNF) et le Laboratoire de Mathématiques et Applications (LMA) de Poitiers afin d’étudier la navigation en milieu confiné dans une optique d’interaction fluide-structures. En complément à un post-doctorat en cours sur une revisite des travaux théoriques sur les effets de confinement hydraulique et ondulatoire pour un bateau fluvial en interaction avec l’ouvrage (typiquement un canal à forme trapézoïdal), nous souhaitons désormais alimenter les études théoriques par des expériences permettant de cribler les modèles ainsi que de guider les modélisateurs vers les modèles pertinents du fait de lacunes dans la compréhension des phénomènes tels que révélées par l’analyse de la littérature et que les expériences pourraient combler.

The aim of the project is to develop, analyze, validate and compare reduced data assimilation technique for 3D incompressible turbulent flows. The point of departure is the stochastic closure modeling procedure and the existing code coupled with the C++ solver Ithaca FV. The PhD student will acquire a broad vision of the data assimilation process and its limitation: from the theory, to the implementation, the data qualification and the experiments. Both synthetic and experimental data will be considered. We shall also consider the efficient treatment of unknown turbulent inflow conditions and the development of efficient hyper-reduction techniques to handle nonlinear terms.

The aim of the project is to develop and analyze a model reduction technique for the simulation of parametric incompressible turbulent (chaotic) flows. The point of departure is the stochastic closure modeling procedure ; we shall consider the efficient treatment of parametric boundary conditions and the development of efficient hyper-reduction techniques to handle nonlinear terms.Application to large-scale three-dimensional problems will be pursued by integrating the methodology in the C++ solver Ithaca FV.

This PhD project aims at modelling the dynamics of long flexible fibers in wall-bounded turbulent flows, in particular close to the walls where the turbulence is inhomogeneous and anisotropic. To tackle this challenging problem, the project will primarily utilize an experimental approach complemented by direct numerical simulations and physical modelling.

The aim of this thesis is to develop new tools and methodology for modelling andcontrol of bistable flows from data, by coupling state-of-the-art machine learning techniques withdynamical system theory. Closed-loop control will be implemented using model predictive control.

Proposition de thèseModélisation stochastique pour la dynamique des particules en turbulence hétérogèneEncadrants : Rémi Zamansky, Pascal Fede, Olivier SimoninContact : remi.zamansky@imft.fr pascale.fede@imft.fr olivier.simonin@imft.fr Financement : Contrats Doctoraux MESRI 2024-2027

The post-doc will run a new experimental setup aiming at reaching the weakly non-linear wave turbulence regime in a stratified (and rotating) fluid. The objective is to test the theoretical predictions of the Weak Turbulence Theory which might be relevant to describe the turbulent dynamics of the oceans at small scales but remains controversial.

A two-year postdoc position on the "Aggregation and Fragmentation of Flexible Fibers in Turbulent flows" is available at Université Côte d'Azur, Nice (Inphyni and LJAD)