SIG35, SIG42, PC Henri Bénard PC Workshop

Geometry, Singularities and Instabilities in Fluids

^{28th - 29th May 2026}

^{Campus Jussieu, Paris, France}

Summary of the objectives of the activity

A part of this workshop will be a follow-up of the conference Vortex & Turbulence, tribute to Laurent Jacquin, held in Ecole Polytechnique, Palaiseau (near Paris), September 10-12 2025. Recent progresses will be presented and discussed for the themes, as follows:

• Linear analysis of complex mean flows, from databases. This deals with the Resolvent Approach, with possible use of data assimilation and IA.More effort will be placed on the feedback to the mean flow from generalized Reynolds stresses, in RANS techniques, beyond the eddy viscosity.

• Role of singularities, in possible connectionwith spontaneous stochasticity and chaotic behaviour. Analyses and measurements in a recent facility of a von Karman flow in CEA Saclay, in close collaboration of ONERA.

• Recent progresses in rotating flows. Turbulent swirling flows in cyclones. Rise of finite-time singularities near the two-dimensional manifold.

• Role of increasing compressibility in turbulent flows

• Stochastic models for epidemic spreading

Provisional list of active participants

• Andrzej Nowakowski (Sheffield U., ERCOFTAC co-organiser, responsible for SIG 42)
• Thomas Michelitsch (d’Alembert, Sorbonne U., local co-organiser)
• Claude Cambon (LMFA, Ecole Centrale de Lyon, responsible for SIG 35)
• julian Scott (LMFA)
• Michael Besterhorn (Cottbus U., DE)
• Waleed Mouhali (Observatory of Meudon, near Paris)
• Thierry Lehner (Observatory of Meudon)
• Abdelaziz Salhi (Université de Tunis)
• Christophe Josserand (Polytechnique, Palaiseau, near Paris)
• Alejandro Alvarez-Laguna (Polytechnique)
• Vincent Mons (ONERA)
• Denis Sipp (ONERA)
• Yves Pomeau (Sorbonne U.)
• John-Christos Vassilicos (Ecole Centrale de Lille)
• Adam Cheminet (with Bérangère Dubrulle, CEA Saclay)
• Basile Gallet (CEA Saclay)
• David Fabre (IMFT Toulouse)

M​ore information to be provided