13 juin 2022

HDR Joran Rolland

HDR defense of Joran Rolland, Assistant Professor at Centrale Lille Institut
Study and hydraulic modeling of an energy storage system by dynamic control of a pump-turbine-valve circuit
Abstract:

This habilitation thesis presents work I have performed during the last decade, after the defence of my PhD thesis. Topically, it presents the study of two main kinds of turbulent flows: transitional wall turbulence and geophysical flows. I have mostly been interested in the rare switches of large scale circulations and radiation of small scale structures in these flows. For this matter, I have contributed to the design and test of rare events simulation methods that can greatly accelerate the computation of the switch trajectories and their probability of occurrence. With these tools, I have been able to study the physical mechanisms of rare events like the collapse of wall turbulence. I have discussed the results using theoretical descriptions of rare events, often based on a large deviations formulation. In parallel, I have designed semi empirical probabilistic models for these flows that have shown their quantitative or qualitative predictive power for rare events and transitional turbulence. These works open perspectives for further study of multistable flow that I am currently performing in LMFL.

Announcement

13 juin 2022, 14h0017h00
LMFL, Batiment M6, Blv Paul Langevin, Cité Scientifique, Villeneuve d'Ascq

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28 mars 2024

Webinar Rui Ni

The Wrath of the Small: Fragmentation of Bubbles in Turbulence by Small Eddies

Rui Ni is an Associate Professor in Mechanical Engineering at Johns Hopkins University and was appointed as the DOE ORISE professor in 2019. Prior to joining JHU, he was the endowed Kenneth K. Kuo Early Career Professor at Penn State University. He received his Ph.D. in the Department of Physics from the Chinese University of Hong Kong in 2011, and worked as a postdoctoral scholar at Yale and Wesleyan University. He received an NSF CAREER award in fluid dynamics, ACS-PRF New Investigator Award, and NASA Early Stage Investigation award. His primary research focus is the development of advanced experimental methods for understanding multiphase flows in many applications, such as energy systems, emulsion, particle ingestion in gas turbines, landings on extraterrestrial bodies, and dust mitigation for future space exploration.