I am Assistant Professor of Fluid Dynamics and Applied Mathematics at DynFluid, a fluid dynamics laboratory part of Arts & Métiers Institute of Technology in Paris, France since September 2016.

Research Activities

Using a dynamical system point of view, most of my research activities are dedicated to the study of the physical mechanisms leading various kind of flows to transition to turbulence and to the modeling of these systems using data-driven techniques.

Transition to turbulence : Transition to turbulence is one of the most important unsolved problem in fluid dynamics. From an engineering point of view, turbulence may be beneficial (e.g. in mixing problems) or detrimental (e.g. in aerodynamics applications). In either case, a better understanding of the physical mechanisms causing the flow to transition to turbulence is needed. This increased understanding may then be used to try to promote or delay transition. In this context, part of my research is dedicated to understanding these mechanisms and predicting the onset of turbulence by using tools from dynamical system theory. In particular, we develop large-scale Newton-Krylov and eigenvalue solvers to perform stability analyses of fully three-dimensional flow configurations. This work has recently culminated in the development of nekStab, a user-friendly toolbox for the spectral element solver Nek5000. This toolbox will be released as open-source very shortly.

Data-driven modeling : Although stability analyses might provide valuable insights into the physics of the flow, it does not necessarily leads to simple models that could be used for real-time control or estimation. Moreover, if one only has access to experimental facilities, such stability analyses are not possible. In order to accomodate for these limitations, one can instead shift from first principles to a data-driven paradigm. In this context, most of my research is dedicated to the development and perfection of innovative data-driven techniques. In particular, close attention is being paid to the data efficiency and robustness of the methods proprosed. Another crucial aspect of my work, in collaboration with Steven Brunton from the University of Washington (Seattle, USA) is the development of interpretable system identification techniques such as SINDy. In addition to the interpretability, we also emphasize the importance of being able to incorporate prior physical knowledge in the modeling procedure, often leading to even more interpretable and robust models.

Postdoctoral Research Opportunity: The French National Agency for Research has funded my 4 years project CONMAN (see here for the complete proposal) whose aim is to improve and develop new data-driven techniques for control and reduced-order modeling purposes, with a strong emphasis in fluid dynamics. I am thus actively looking for a postdoctoral collaborator to work with me in Paris! The position is fully funded for a duration of up to 18 months. If you are interested, please do not hesitate to get in touch!

Current members

Mohamed El Hawary is an Egyptian student and the newest member of this research group. He just started his Ph.D. under the co-supervision of Antoine Dazin (Arts & Métiers, Lille), Francesco Romano (Arts & Métiers, Lille) and myself. The core of his work will be dedicated to the development of efficient and robust control strategies for turbomachines with a special emphasis on data-driven techniques such as DMD with control, ERA and Reinforcement Learning.

Former members

Gabriele Nastro was an Italian PostDoc in the lab. He defended his thesis entitled Non-modal stability of variable-density roud jets in October 2020 under the supervision of Laurent Joly and Jérôme Fontaine at ISAE, Toulouse. He has been working on the sensitivity to localized actuators of the high Reynolds number flow past a NACA airfoil in pre-stall conditions. This work is part of the CleanSky (H2020) European project PERSEUS in collaboration with the University of Orléans. Since early November 2022, he is Assistant Professor at ISAE, Toulouse (France).

Ricardo Frantz is a Brazilian researcher who recently defended is PhD thesis entitled Floquet analyses of complex flows. This work was prepared under the joint supervision of myself and Jean-Christophe Robinet. Over the past three years, the core of his work has been to implement Newton-Krylov and eigenvalue solvers for large-scale systems such as the ones resulting from the discretization of the Navier-Stokes equations. He is also one of the main developer of nekStab, our in-house toolbox for large-scale stability analyses in Nek5000 which will be released as open-source shortly. As of June 2022, he will start as a postdoctoral researcher at Institute Jean le Rond d’Alembert working with Taraneh Sayadi.

Cosimo Tarsia Morisco did his Ph.D. under the joint supervision of Jean-Christophe Robinet and myself. His thesis, entitled Nonlinear dynamics and linear stability of over-expanded nozzle flows was funded by Ariane Group and was defended on December 2020 in front of Abdellah Hadjadj (INSA, Rouen), Sébastien Deck (ONERA, Paris), Lutz Lesshafft (Ecole Polytechnique, Paris), and Vincent Jaunet (Institut Pprime, Poitiers). His manuscript can be found here. He now is a Research Engineer at INRIA, Paris.