报告主题：Controlling flow through viscosity manipulation

报 告 人：Nigel Mottram（格拉斯哥大学）

报告时间：2024年3月21日16:30-17:30

报告地点：文波楼110教室

摘  要：The flow of a fluid around a solid object is an everyday phenomenon – water flowing around the rocks in a stream, air being funneled through a gap between buildings – and changing the shape of a solid object allows active manipulation of the direction of flow – ailerons and the rudder on an aircraft work in exactly this way. But in a microfluidic device, where we consider extremely small volumes of liquid, moving at sub-millimeter lengthscales, moving solid objects to affect the flow can be difficult, with fine control of the flow being challenging.However, the active control and manipulation of flow streamlines, as well as interfaces between fluids, at micron and millimeter scales often plays an important role in many industrial and technological applications, and so significant effort has gone into this area of research. In this talk I will present some recent work on how liquid crystal materials offer a new way to tackle these challenges. I will begin with an introduction to the world of liquid crystals – which are viscoelastic liquids in which microstructure and flow are intrinsically linked – and then show how, through electrostatic manipulation of the microstructure and thus the viscosity, it is possible to create controlled manipulation of streamlines and free-surfaces – equivalent to placing a solid or porous object in the way of the flow, with the added benefit of being able to actively alter the porosity. In this work we have considered two examples to demonstrate the effect: flow of a liquid crystal rivulet down an inclined substrate,

报告人简介：Prof. Nigel Mottram is a Professor of Applied Mathematics and the Head of the School of Mathematics and Statistics at the University of Glasgow. After a degree in Mathematics at the University of Oxford, he started his research career at the University of Bristol in 1992, working with Prof John Hogan in the Department of Engineering Mathematics on modelling liquid crystals - the main component of the Liquid Crystal Displays we have in our phones, TVs, laptops etc. After postdoctoral research in Bristol, Oxford, Pisa and Rome he moved to a lectureship in the Department of Mathematics at the University of Strathclyde in 1999. In 2020 he moved to a Professorship at the University of Glasgow, and in 2023 because the Head of the School of Mathematics and Statistics. Since the start of his PhD he has been involved in the development of theoretical models applied to real world applications, in particular anisotropic fluid systems used in optoelectronic devices. He has worked in collaboration with companies in Germany, USA, South Korea and the UK,