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    Webinar: Dynamics of Bubble Nucleation

    Event Details:

    • Date:         Tuesday, 18 January 2022
    • Time:         Starts: 16:00
    • Venue:       Live streaming of the discussion will be available on Zoom (Password: VsSCz1)
    • Speaker:    Prof. Carlo Massimo Casciola, Sapienza University of Rome



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    CaSToRC, the HPC National Competence Centre,
     invites you to the EuroCC and SimEA Online Seminar Series

    The webinar will be in English and the live stream is open to the public.
    Live streaming of the discussion will be available on Zoom (Password: VsSCz1)
    Images and/or recordings of our open public events may be used by The Cyprus Institute for dissemination purposes including print and digital media such as websites, press-releases, social media, and live streaming.

     

     

    Abstract


    When the pressure falls below a critical level (cavitation) or the temperature raises above a threshold (boiling), the liquid-vapor transition takes place. The process starts with the nucleation phase, a rare event which is deeply routed in the atomistic nature of the fluid. Successively, depending on the local thermodynamic conditions, the bubble may grow to macroscopic size and couple to the inertial dynamics of the surrounding fluid. In the classical approach each phase is treated separately.

     
    Classical Nucleation Theory (CNT) deals with the nucleation rate (number of bubbles formed per unit time and volume). Once the bubble is formed, the celebrated Rayleigh-Plesset equation, or extensions therein, is classically used to describe the bubble dynamics. After reviewing the state of the art in the field, purpose of the talk is discussing a comprehensive model able to provide a unified description of the different phenomenologies described above. The model is based on the capillary Navier-Stokes equation where the liquid-vapor interface is treated by a diffuse interface model accounting for the relevant thermodynamic properties of the fluid (e.g., equation of state, phase change and latent heat). In order to describe the nucleation phase, a noise term is included (fluctuating hydrodynamics) leading to a system of stochastic partial differential equations with the unique capability of describing the nucleation of vapor cavities from the liquid in the context of continuum mechanics.
     
    Several examples of numerical solutions will be used to illustrate how the model can be effectively implemented on the HPC facilities made available under the auspices of PRACE. They include bubble collapse in free-space and near solid walls and their homogenous and heterogeneous nucleation in different geometries. New results concerning nucleation and bubble dynamics in a flowing liquid and in a confined cavity will also be presented to finally touch upon the rare event techniques aimed at accurately extracting the cavitation pressure for actual water in a wide range of temperatures.

     

    Bibliography

    - Magaletti, Gallo, CMC, Water Cavitation From Ambient to High Temperature, Scientific Reports 2021.
    - Gallo, Magaletti, CMC, Heterogeneous bubble nucleation dynamics”, Journal of Fluid Mechanics 2021.
    - Gallo, Magaletti, Cocco, CMC, Nucleation and growth dynamics of vapor bubbles, Journal of Fluid Mechanics 2019.
    - Gallo, Magaletti, CMC, Thermally activated vapor bubble nucleation: the LandauLifshitz/Van der Waals approach”, Phys. Rev. Fluids. 2018.

     

    About the Speaker

    c m casciolaCarlo Massimo Casciola leads a research group of about 20 among researchers, postdocs and PhD students working on the fluid dynamics of complex flows with a chiefly theoretical and numerical approach. His research is oriented to fundamental and numerical modelling, with substantial interactions with several neighbouring disciplines, such as engineering, physics, material science, chemistry, mathematics, biology, and medicine.

    Most of the topics are characterised by the coupling of macroscopic flows with a micro-structure. After being awarded the ERC Advanced Grant 2013, BIC: Following Bubbles from Inception to Collapse, a significant part of the research work has been focused on different aspects of cavitation, e.g. heterogeneous nucleation, wettability, bubble collapse modelling, bubble-wall interactions.

    The tools employed span from Direct and Large Eddy Simulation, to Phase Field Models, Free Energy Methods, and Molecular Dynamics techniques specialised for Rare Events. Significant contributions concerns technics and models for Wettability and heterogeneous nucleation on complex surfaces; Phase field methods for (nano-)bubble dynamics and cavitation; Direct numerical simulations of polymer drag reducing flows; Scaling laws and energy fluxes in inhomogeneous turbulent flows; Particle transport in turbulent flows in the two-way coping regime. Recently, the research interests extended to experimental aspects of bubble dynamics, cavitation and micro fluidics for application in biology and medicine

     

     

    Download the Winter-Spring 2022 Online EuroCC & SimEA Seminar Series Programme here.

    Screenshot 2022 04 12 165256 


    The EuroCC project has received funding from the European Union’s Horizon 2020 research and innovation programme grant agreement No. 951732

    European Union's Horizon 2020 Research and Innovation Programme

    This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 810660




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    Additional Info

    • Date: Tuesday, 18 January 2022
    • Time: Starts: 16:00
    • Speaker: Prof. Carlo Massimo Casciola, Sapienza University of Rome

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