European Society of Rheology (ESR)

The European Society of Rheology is open for everyone interested in rheology in all countries of Europe. Rheology is defined as the science of the deformation and flow of matter which means that rheology in some form enters almost every study of material properties. The ESR involves rheologists engaged in both industrial and academic research and development and is therefore a common meeting ground for engineers, physicists, chemists and biologists with a common interest in rheology

 

Pier Luca Maffettone is the 2023 Weissenberg Awardee

Pier Luca Maffettone is Professor of Chemical Engineering at the University Federico II of Naples, Italy. He served from 2006 to 2011 as Coordinator of the PhD program in Chemical Engineering, from 2008 to 2012 as President of the Bachelor and of the Master of Science Courses in Chemical Engineering, from 2013 to 2018 as Chairman of the Department of Chemical, Materials, and Production Engineering, and since 2020 as Member of the University Board. He co-chaired AERC 2007 in Naples. He also served from 2014 to 2020 as a Member at large of the Executive Committee of the European Society of Rheology. His scientific activity is focused on modeling and simulation of the flow behavior of soft matter. He is currently member of the Editorial Board of Rheologica Acta and of Journal of Non-Newtonian Fluid Mechanics, and a Fellow of the Society of Rheology. He was visiting scientist at the University of Delaware (USA), at the Katholieke Universiteit Leuven (Belgium), at the Stanford University (USA), and at the Okinawa Institute of Science and Technology (Japan).

In the early stage of his scientific career, working in the group of G. Marrucci he analyzed the rheology of liquid crystalline polymers within the framework of the rigid rod model of Doi and Hess both in bulk and as monolayers in collaboration with the group of Gerry Fuller at Stanford. Later, he showed the occurrence of “Rheo-Chaos” in shear flows. He proposed, in collaboration with Mario Minale, a simple but effective toy model for the deformation of a drop in linear flows with Newtonian and/or viscoelastic liquids. The predictions of this model have been used as a rheological guide in several polymer blends and emulsion applications. The work on cross-flow migration of particles suspended in viscoelastic liquids started as a joint effort together with the group of Jan Vermant in Leuven and with Martien Hulsen in Eindhoven. The cross-streamline migration of a spherical particle in a viscoelastic fluid flowing in a wide slit microdevice was investigated through 3D finite element simulations. A multiplicity of stable positions was discovered, whereby the particle is driven towards the channel center-plane or the closest wall depending on its initial position through the gap, thus leading to the existence of an unstable separatrix. This phenomenon, a viscoelastic reversal of the well-known Segré-Silberberg effect driven by inertia, led to the development of Rheo-Engineered microfluidics for Lab-On-a-Chip applications. The cross-flow particle migration was also used to build a micro-rheometer to estimate relaxation times of viscoelastic fluids as low as milliseconds. He recently addressed, in collaboration with Gerry Fuller, the dynamics of film rupture with viscoelastic interfaces, revealing the existence of a novel breakage scenario.

Award Citation: For contributing to a fundamental understanding of particle migration in viscoelastic fluids, also leading to the development of useful micro-rheological devices. For developing simple and successful models for the rheology of dilute blends of immiscible fluids.

Duncan Hewitt is the 2023 Oldroyd early career Awardee

Duncan Hewitt is Associate Professor at University College London. He is an applied mathematician and rheologist, interested in using mathematics to model and understand physical processes in the world around us most notably for yield stress and other complex fluids. He holds undergraduate degrees (BA and MMath) in Mathematics and a PhD in Applied Mathematics, all from the University of Cambridge. Following the award of his PhD in 2014, he held Research Fellowships firstly in the Department of Mathematics at the University of British Columbia, Vancouver (2014-2015) as a Killam Postdoctoral Research Fellow, followed by a Research Fellowship at Gonville and Caius College, University of Cambridge (2015-2019). In 2019 he was appointed Lecturer in the Department of Applied Mathematics at University College London and promoted to Associate Professor in 2022.

The most significant early contribution of Duncan  on the topic of yield stress fluids is with the paper “Viscoplastic boundary layers” published in JFM.  In this paper, Duncan and the team revisited one of Oldroyd’s 1947 papers concerned with the same problem. Oldroyd derived a nonlinear form of the boundary-layer equations for a Bingham model but there were significant doubts within the literature that these were actually correct. In revisiting the problem using theoretical and numerical approaches, Duncan and the team were able to demonstrate that the viscoplastic boundary layers postulated by Oldroyd (based on theoretical arguments alone) did form exactly as envisioned by him. Duncan’s strongest contribution to the field is in the area of “swimming” in yield stress fluids. Starting with an analysis of GI Taylor's canonical ‘swimming sheet', idealised versions of squirming organisms, and long, thin worm-like motions have been studied by Duncan, the latter of which involves a generalisation of classical slender-body theory for viscoplastic fluids.  Duncan has also made important contributions to our understanding of viscoplastic dam breaks, viscoplastic free surface flow around obstacles, and viscoplastic flow through Hele-Shaw cells featuring various obstructions.  In an entirely separate series of papers, he has also made important contributions to our understanding of how rheology affects the compressional mechanics of deformable porous suspensions.

Award Citation: Dr Duncan Hewitt is an applied mathematician, responsible for a series of beautiful fundamental studies investigating yield stress fluids, most notably for probing locomotion through such “viscoplastic” fluids. Duncan combines rigorous analytical work with high-quality simulations to provide fundamental physical understanding and insight.

Access to Rheologica Acta

Access to Rheologica Acta and Applied Rheology is free for all individual members of the ESR. Please access Rheologica Acta via the 'Member area'.

All participants of AERC 2022 (Seville/Spain) are automatically individual members of the ESR until August 2023.

Rheologica Acta Publication Award

At every AERC or ICR, the editors of Rheologica Acta present the publication award sponsored by Anton Paar. This award gets selected by three editorial board members based on a preselection by the editors and is aimed to highlight the type of work which the journal likes to see published.

The 2023 Rheologica Acta Publication Award was given to:

Nikola Dudukovic, Megan Ellis, Moira Foster, Rebecca Walton, Du Nguyen, Brian Giera, Rebecca Dylla-Spears: 3D printing of void-free glass monoliths: rheological and geometric considerations, Rheologica Acta 61 (2022) 773-784.

The entire list of the Rheologica Acta Publication Awards and the Weissenberg Lecture papers can be found in the Archive.