ERCOFTAC Worshop

Onset of Turbulence and Singular Flows

This workshop was first motivated by two very recent studies, the first one is by Bérangère Dubrulle and coworkers, on interacting singularities as solutions of Navier-Stokes equations, or pinçons; the second is by Yuli Chashechkin on Conventional Partial and Complete Solutions of the Fundamental Equations of Fluid Mechanics in the Problem of Periodic Internal Waves with Accompanying Ligaments Generation. In addition, the role of singularities in the dissipation process is a very promising topic, rather old, but with recent developments towards applications to actual flows in engineering. For instance, such dissipative processes have suggested an alternative to conventional RANS modelling, regarding the Boussinesq approximation and the building of the Reynolds stress tensor, by Yves Pomeau, Christophe Josserand, and coworkers; a new insight to turbulence in a layer at a wedge can be investigated.

This topic is relevant in the geophysical context, with the connection to SIG 14, whose recent coordinator is Tomas Bodnar. In this line, the workshop can be seen as a first meeting, in order to gather specialists of geophysics, fluid mechanics, and mathematics, around Euler and Navier-Stokes equations. In this workshop, experimental studies for waves, namely in stratified turbulence, will be emphasized: this offers the opportunity to compare the mathematical approach to singularities to their experimental search.

The location chosen is the resort place managed by IGESA, in the Porquerolles island, not far from Toulon. We are very happy to propose an event partly in presence, with a so nice surrounding, after the past successive lockdowns, since, for the SIG 35 and the Henri Bénard Pilot Centre, the last workshop in presence took place in January 2019.

Organization Committee

• Tomáš Bodnár, Czech Technical University in Prague
• Claude Cambon, Laboratoire de Mécanique des Fluides et d’Acoustique, Ecole Centrale Lyon
• Bérangère Dubrulle, Service de Physique de l’Etat Condensé
• Philippe Fraunié, Mediterranean Institute of Oceanography, Université de Toulon
• Mikhael Gorokhovski, Laboratoire de Mécanique des Fluides et d’Acoustique, ECL
• Christophe Josserand, Laboratoire d’Hydrodynamique LADHYX
• Yves Pomeau, Laboratoire d’Hydrodynamique LADHYX

IGESA Porquerolles island, 8 - 10 July 2021

Program

Thursday July 8

14:30 - 16:00 Opening session : Turbulence

• Alain Pumir, ENS Lyon
  Self-attenuation of extreme events in turbulence

• Emmanuel Villermaux, IRPHE
  Direct Cascade, Finite-time singularity, Richardson scaling, and Senkou-Hanabi

• Sergio Chibbaro, Institut Jean Le Rond D’Alembert
  Wave-turbulence and thermalisation in weakly nonlinear chains

• Yves Pomeau, LADHYX
  Real turbulence:  a derivation of von Karman-Prandtl law of the wall and more

• Christophe Josserand, LADHYX
  Singularity driven turbulence

16:00 - 20:00 : Room taking and dinner

20:00 - 21:30 : Special session in memory of Antonin Novotny

• Eduard Feireisl, Institute of Mathematics, Prague
  On the relevance of stochastic models in statistical compressible turbulence

• Jiří Fürst, Czech Technical University, Prague
  Transition and turbulence models within RANS framework

• Tomáš Bodnár, Czech Technical University, Prague
  On numerical simulations of wall bounded stratified flows

• Matteo Caggio, Institute of Mathematics, CAS, Prague
  Closure scheme for stably stratified turbulence without critical Richardson number

Friday July 9

8:30 - 10:00 Observations and experiments

• Yuli Chashechkin, Ishlinsky Institute for Problems in Mechanics, Moscow [on line]
  Environmental flow dynamics and structure: role of regular and singular perturbed components

• Joel Sommeria, Laboratoire des Ecoulements Géophysiques et Industriels Grenoble
  Entrainment and mixing at a density interface: statistical mechanics closure versus laboratory experiments

• Nicolas Mordant, Laboratoire des Ecoulements Géophysiques et Industriels Grenoble
  Stratified turbulence forced by waves: experiments in the Coriolis facility

• Patrice Le Gal, IRPHE Marseille
  Geometrical focusing of surface waves and their breaking

10:00 - 10:30 : Coffee break

10:30 - 12:00 Processes

• Vladimir Zeitlin, Laboratoire de Météorologie Dynamique Paris
  Coherent structures and transition to turbulence in thermal and magnetic rotating shallow water

• Kirill Zibin Lebedev Institute
  No feedback is possible in small-scale turbulent magnetic field

• Nathaniel Saura, PIIM, Aix Marseille University
  Modeling of the Subgrid Stress Tensor in Homogeneous Isotropic Turbulence  using 3D Convolutional Neural Network

• Bérengère Dubrulle, Service de Physique de l’Etat Condensé [on line]
  Investigation and modelling (quasi) singularities in turbulent flows

• Mikhael Gorokhovski, Laboratoire de Mécanique des Fluides et Acoustique Lyon [on line]
  Stochastic models of acceleration: application to under-resolved flows at a high Reynolds number

12:00 - 13:00 Lunch

Free afternoon in Porquerolles Island

19:00 - 20:00 Dinner

Saturday july 10

8:30 - 10:00 Models and applications

• Sergei Nazarenko, Université côte d’Azur
  Formation of zonal jets as a Bose-Enstein condensation process

• Ying Zhu, Université côte d’Azur
  Direct DNS method for homogeneous turbulent flow

• Laurent Jacquin, ONERA
  Jets [on line]

• Luminita Danaila, Morphodynamique Continentale et Côtière (M2C) [on line]
  Extreme events for temperature and rainfall  in the context of climate variability

• Christos Vassilicos, Laboratoire de Mécanique des Fluides de Lille [on line]
  And what about trying something like a bit of theory of non-homogeneous turbulence?

10:00 - 10:30 coffee break

10:30 - 12:00 Round table / Open discussion

• Paul Clavin, IRPHE

12:00 Workshop closure, lunch and departure