10 juin 2021

Webinar Alfredo Soldati

Alfredo Soldati is Professor of Mechanical Engineering at TU Wien. His research focuses on physics and engineering of multiphase flows. Dr. Soldati received the 2007 ASME Robert Knapp award, the 2015 ASME Lewis Moody award, and in 2020 the ASME Freeman Scholar Award. In 2013 he was elected Fellow of the American Physical Society and in 2020 was elected fellow of EUROMECH. He also received the International Prize and Gold Medal Panetti–Ferrari 2018 from Accademia delle Scienze, Torino, Italia. He is currently the Rector of the International Center for Mechanical Sciences (CISM) and the co-Editor in Chief of International Journal of Multiphase Flow. He maintains a part time position at the University of Udine, Italy
Modelling and Computation of Interfaces in Turbulent Multiphase Flows

Abstract: Droplets carried in turbulent fluids rely, for their existence, on tiny interfaces. Interfaces are not property of the drop or of the the carrier fluid and are inherently a non-place. However, in environmental and industrial processes, their role is enormously important since it is across the interfaces that momentum, heat and mass transfer fluxes coupling the drop to the carrier fluid occur: the accurate determination of their position, shape and interaction with the fluid turbulence is crucial to predict physical phenomena, and industrial and environmental processes. To this aim, Direct Numerical Simulation (DNS) of turbulence and accurate tracking of the interface are required, but the range of scales involved for most ofpractical environmental and industrial applications is so wide that performing this task is a formidable challenge for present day computers: The grid resolution for DNS of turbulence is of the order of the Kolmogorov scale, but of course physical interfaces have a much smaller scale (order of few molecules) making the direct resolution unfeasible. In this talk, we will briefly review the current computational methodologies used to interfaces and the we will focus on the phase-field approach in turbulent flows: In this Eulerian approch, the phase distribution is described by the order parameter φ. We will examine several flow instances and phenomena ranging from turbulent stratified flows to turbulent dispersion of drops and bubbles so to reveal potentials and limitations of the phase-field method. Interface interactions with turbulence, coalescence and
breakup phenomena for different values of fluids density and viscosity will be discussed in connection with the characteristics of turbulence. Finally, the physics modelling and the method required to include the effect of surfactants will also be examined.

Abstract in PDF

10 juin 2021, 16h3017h30
please contact F. Romano for the link