Industrial and Applied Mathematics Seminar

Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

Past events in this series
Tomorrow
16:00
to
17:30
Susana Gomes
Abstract

The flow of a thin film down an inclined plane is an important physical phenomenon appearing in many industrial applications, such as coating (where it is desirable to maintain the fluid interface flat) or heat transfer (where a larger interfacial area is beneficial). These applications lead to the need of reliably manipulating the flow in order to obtain a desired interfacial shape. The interface of such thin films can be described by a number of models, each of them exhibiting instabilities for certain parameter regimes. In this talk, I will propose a feedback control methodology based on same-fluid blowing and suction. I use the Kuramoto–Sivashinsky (KS) equation to model interface perturbations and to derive the controls. I will show that one can use a finite number of point-actuated controls based on observations of the interface to stabilise both the flat solution and any chosen nontrivial solution of the KS equation. Furthermore, I will investigate the robustness of the designed controls to uncertain observations and parameter values, and study the effect of the controls across a hierarchy of models for the interface, which include the KS equation, (nonlinear) long-wave models and the full Navier–Stokes equations.

  • Industrial and Applied Mathematics Seminar
13 February 2020
16:00
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17:30
Professor Panos Kevrekidis
Abstract

Nonlinear generalizations of the Schrödinger equation are of wide applicability to a range of areas including atomic and optical systems, 
plasma physics and water waves.  In this  talk we revisit some principal excitations in atomic and optical systems (such as Bose-Einstein condensates and photo-refractive crystals), namely dark solitonic fronts in single-component systems, and dark-bright waves in multi-component systems. Upon introducing them and explaining their existence and stability properties in one spatial dimension, we will extend them both in the form of stripes and in that rings in two-dimensions, presenting an alternative (adiabatic-invariant based) formulation of their stability and excitations. We will explore their filamentary dynamics, as well as the states that emerge from their transverse (snaking) instability. Then, we will consider these structures even in three dimensions, in the form of planar, as well as spherical shell wave patterns and generalize our adiabatic invariant formulation there. Finally, time permitting, we will give some glimpses of how some of these dynamical features in 1d and 2d generalize in a multi-orbital, time-dependent quantum setting.

  • Industrial and Applied Mathematics Seminar
20 February 2020
16:00
to
17:30
Marie Elisabeth Rognes

Further Information: 

Short bio:

Marie E. Rognes is Chief Research Scientist and Research Professor in Scientific Computing and Numerical Analysis at Simula Research Laboratory, Oslo, Norway. She received her Ph.D from the University of Oslo in 2009 with an extended stay at the University of Minneapolis, Twin Cities, Minneapolis, US. She has been at Simula Research Laboratory since 2009, led its Department for Biomedical Computing from 2012-2016 and currently leads a number of research projects focusing on mathematical modelling and numerical methods for brain mechanics including an ERC Starting Grant in Mathematics. She won the 2015 Wilkinson Prize for Numerical Software, the 2018 Royal Norwegian Society of Sciences and Letters Prize for Young Researchers within the Natural Sciences, and was a Founding Member of the Young Academy of Norway.

Abstract

Your brain has its own waterscape: whether you are reading or sleeping, fluid flows around or through the brain tissue and clears waste in the process. These physiological processes are crucial for the well-being of the brain. In spite of their importance we understand them but little. Mathematics and numerics could play a crucial role in gaining new insight. Indeed, medical doctors express an urgent need for modeling of water transport through the brain, to overcome limitations in traditional techniques. Surprisingly little attention has been paid to the numerics of the brain’s waterscape however, and fundamental knowledge is missing. In this talk, I will discuss mathematical models and numerical methods for the brain's waterscape across scales - from viewing the brain as a poroelastic medium at the macroscale and zooming in to studying electrical, chemical and mechanical interactions between brain cells at the microscale.
 

  • Industrial and Applied Mathematics Seminar
27 February 2020
16:00
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17:30
Professor Peter Howell
Abstract

Motivated by the manufacture of carbon-fibre components, we consider the smooth draping of loosely woven fabric over rigid obstacles, both smooth and non-smooth. The draped fabric is modelled as the continuum limit of a Chebyshev net of two families of short rigid rods that are freely pivoted at their joints. This approach results in a system of nonlinear hyperbolic partial differential equations whose characteristics are the fibres in the fabric. The analysis of this system gives useful information about the drapability of obstacles of many shapes and also poses interesting theoretical questions concerning well-posedness, smoothness and computability of the solutions. This is joint work with Hilary and John Ockendon.

  • Industrial and Applied Mathematics Seminar
5 March 2020
16:00
to
17:30
Valentina Balbi
Abstract

Biological soft tissues are particularly common in nature. For instance, many organs in the human body such as the skin, the brain, the gastro-intestinal system are made of soft tissues. The brain, among all is particularly soft and delicate. Following an impact to the skull, brain matter can experience large stretches, possibly resulting in Diffuse Axonal Injury (DAI), which is the second leading cause of death from traumatic brain injury. Previous studies have focused on linear (uni-axial) stretches of brain to investigate DAI, but in reality brain matter undergoes a mix of deformation modes during an accident. This talk will focus on the mechanical behavior of the brain under torsion (twisting). In collaboration with University College Dublin, we collected data from torsion tests on (pigs) brain samples and modelled the experiments to finally quantify the elastic properties of the brain tissue. I will show that torsional impacts, such as a hook punch in boxing and a side impact in a car accident can also lead to dangerous levels of stretch compatible with DAI.

  • Industrial and Applied Mathematics Seminar
12 March 2020
16:00
to
17:30
Professor Elisabeth Guazzelli
Abstract

Suspensions are composed of mixtures of particles and fluid and are ubiquitous in industrial processes (e.g. waste disposal, concrete, drilling muds, metalworking chip transport, and food processing) and in natural phenomena (e.g. flows of slurries, debris, and lava). The present talk focusses on the rheology of concentrated suspensions of non-colloidal particles. It addresses the classical shear viscosity of suspensions but also non-Newtonian behaviour such as normal-stress differences and shear-induced migration. The rheology of dense suspensions can be tackled via a diversity of approaches that are introduced. In particular, the rheometry of suspensions can be undertaken at an imposed volume fraction but also at imposed values of particle normal stress, which is particularly well suited to yield examination of the rheology close to the jamming transition. The influences of particle roughness and shape are discussed. 

  • Industrial and Applied Mathematics Seminar
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