HDR defense Georg F. DIETZE

Tuesday, May 24, 2022 at 14:00, Laboratoire FAST

Large auditorium, Pascal building (530), rue André Rivière, 91405 Orsay

ZOOM broadcast: please send me an email (georg.dietzeATuniversite-paris-saclay.fr)

Abstract: My research concerns the hydrodynamics of thin liquid films: (i) falling liquid films subject to the Kapitza instability; (ii) annular liquid films in cylindrical geometries subject to the Plateau-Rayleigh instability; (iii) liquid films or vapour layers subject to the Rayleigh-Taylor and Marangoni instabilities; and (iv) spreading liquid films in interaction with microparticles. For the first three configurations, where the flow is subject to long-wave interfacial instabilities, I have developed low-dimensional models based on the weighted residual integral boundary layer (WRIBL) approach. My contribution has been to extend this approach to two-fluid film flows, where the liquid film is in contact with an active outer fluid, e.g. a falling liquid film sheared by a counter-current gas flow. In addition, I have applied direct numerical simulation techniques based on the full Navier-Stokes equations. A substantial part of my work has been dedicated to falling liquid films, and, in particular, how an adjacent gas flow affects their linear stability and the dynamics and stability of nonlinear surface waves. Thereby, I have focused on strongly-confined configurations, such as minichannels or narrow tubes, and the role of surface waves in causing occlusion/flooding events and heat/mass transfer intensification. I have also worked on the occlusion of pulmonary airways by mucus films, the acceleration of wetting via microparticles, and secondary instabilities in thin films subject to the Rayleigh-Taylor instability.