The department of Mathematics and Statistics at the University of Limerick invites you to a seminar by Prof. Jose Maria Montanero (Universidad de Extremadura):
Title: On the dynamics of liquid bridges and pendant drops of complex fluids
Abstract: On the dynamics of liquid bridges and pendant drops of complex fluids The expression “complex fluids” has been coined to refer to liquids with a non-Newtonian behavior caused by the presence of macromolecules, colloids, suspensions… in the bulk and/or surface active substances in the interface. An important subcategory of such fluids is constituted by dilute viscoelastic liquids (the so-called Boger fluids) and Newtonian liquids whose interfaces are loaded with insoluble surfactants. These liquids appear in a large variety not only of industrial and technological applications but also of biological systems. The understanding of the complex interplay between the macromolecules and the Newtonian matrix containing them is far from being satisfactorily understood. Liquid bridges and pendant drops are excellent testbeds to improve understanding of surface-tension driven flows occurring in these liquids. In this talk, we will present some recent theoretical and experimental results on the dynamics of those fluid configurations. We will consider both the linear dynamics and weakly-nonlinear dynamics resulting from the vibration at frequencies close to the first resonance frequency, as well as the fully non-linear process leading to the liquid bridge/pendant drop breakup. Our results will show the need to complete the commonly used theoretical models, and the inability of some of them to properly describe very simple experiments. Specifically, we will uncover the effects of the shear and dilatational surface viscosities commonly neglected in the dynamics of surfactant-laden pendant drops and liquid bridges. Also, we will show the inconsistency very recently found between experiments conducted with dilute polymer solutions and the corresponding theoretical predictions of linear viscoelastic models. L. Anna, Droplets and Bubbles in Microfluidic Devices, Ann. Rev. Fluid Mech. 48, 285-309 (2016). Ponce-Torres, M. A. Herrada, J. M. Montanero, and J. M. Vega, Linear and nonlinear dynamics of an insoluble surfactant-laden liquid bridge, Phys. Fluids 28, 112103 (2016); Ponce-Torres, J. M. Montanero, M. A. Herrada, E. J. Vega, and J. M. Vega, Influence of the Surface Viscosity on the Breakup of a Surfactant-Laden Drop, Phy. Rev. Lett. 118, 024501 (2017).
This seminar will take place on Friday 13th October , at 4 p.m, in Room A2-002.
If you have any questions regarding this seminar, please direct them to Iain Moyles (061 233726, iain.moyles@ul.ie).
A full list of upcoming seminars can be found at https://ulsites.ul.ie/macsi/node/48011
Supported by Science Foundation Ireland funding, MACSI - the Mathematics Applications Consortium for Science and Industry (www.macsi.ul.ie), centred at the University of Limerick, is dedicated to the mathematical modelling and solution of problems which arise in science, engineering and industry in Ireland.
