There are objectives which motivate us to organize this Workshop:

• The first is to gather experts from the turbulence field after this hard and long period of Covid 19 lockdown. Everyone will be welcome to present a talk on what “keeps his heart beating so fast” around the multiscale physics in one-and-two phase turbulence.
• The second is to extend an interface between two GDRs, one is the GDR 2865 on the phenomenology of turbulence, and another is the GDR 2042 on the transfer and interfaces. Two coordinators of those GDRs will present a short introduction to their GDR.
• The third objective takes its interest from the actuality.

Today, for the first time in history, fluid mechanics scientists are more popular than the Beatles and are much more popular than nuclear scientists (dream come true!). Everybody in the world contributes daily to the fluid mechanics experiment referred to as “wash your hands and keep social distancing”. In such circumstances, we also need to contribute in the understanding of the new domain “TORS” – turbulence of respiratory sprays. That is why, all kind of discussions on:

• high-speed production of droplets under accelerating/decelerating air-blast,
• turbulent dynamics and clustering of droplets in air jets (with and without buoyancy),
• droplets evaporation under highly turbulent conditions,
• new ways of the room ventilation,
• the improved methods in pathogen droplets removal, etc., will be very welcome to this Workshop.

Frankly speaking, we discuss about the organization of this workshop since last spring and like a sailor's wife waiting for a calm sea with hope after a tempest, we observe carefully the Covid pandemic statistics in France, and particularly in Lyon. At the moment in the Ecole Centrale, we teach in person, but nobody knows how the situation may change in few weeks. That is why each participant is free to choose his attending between online or in person.

You are cordially invited to participate. During the three coming weeks, please send us your proposal by email to:

mikhael.gorokhovski@ec-lyon.fr