Fluids are everywhere and take many forms, from simple gases to complex suspensions. They are essential to life, and feature in many ways in a host engineering applications.
Our research in this area encompasses a diverse range of applications across many length scales, from the control of tiny droplets of ink and the study of microchannel flows to the optimisation of large-scale industrial ovens and air conditioning systems. A defining feature of our approach to fluid mechanics research is the powerful combination of both experimental and modelling techniques to develop a deep understanding of flows and processes. We have excellent experimental and computational facilities to support both. Our research topics are inspired both by industrial or societal drivers and by fundamental fluid mechanics challenges, and we have very good links with industry.
Flows involving surfaces and interfaces are obviously of great interest to us, and a key area of research is the dynamics of liquid droplets, which arise in many different applications. Examples include inkjet printing, drug manufacture, medicinal sprays, emulsion formation, condensation control, pesticide delivery, fuel/water filtration and separation, and shear-driven droplets (such as one sees on the windscreen of a moving vehicle). Associated with the interaction of droplets with surfaces is the phenomenon of wetting, which is also crucial in many other areas from lab-on-a-chip applications to coating processes to enhanced oil recovery. We have a number of current projects focusing on this fascinating and fertile fundamental topic.
iETSI has a long history of research into the fluid mechanics of thin liquid films and associated coating and printing processes, and this continues to be an active research area, particularly in the context of flows over complex surface topographies, such as the surfaces of leaves. Fluid-structure interactions are becoming increasingly important, especially for flows within or around biological tissue, and links are emerging with our colleagues working in biomedical engineering.
Another important research area is the influence of fluid flow on mass transport, mixing, erosion, and other phenomena such as heat transfer, nanofluid performance, and chemical reactions. Indeed the exploitation of microfluidic systems has great potential in continuous chemical processing via reaction pathways that are for example too hazardous for batch processing.
Much of our work is cross-disciplinary, for example with the School of Chemistry we are developing liquids that give controlled droplet sizes and exploring the influence of flow on chemical reactions, with the Faculty of Biological Sciences we are controlling living surfaces, and with the School of Mathematics and the School of Computing we are developing better simulation algorithms. We also work with a wide range of major industrial partners from across a broad sector of industry including medicine, manufacturing, oil and gas, and the transport industry.
Flick through this Research Review and you will see that fluid mechanics features in many of the different iETSI research areas. On the following pages, you can read more about a selection of other projects where fluid mechanics is being developed and applied.
Current and future research
Our busy microfluidics / interfacial fluids laboratory is equipped with various flow visualisation and characterisation techniques including micro-PIV (particle image velocity), high-speed, micro- and time lapse photography, as well as a plasma treatment chamber for surface preparation, a variety of light sources including a dual pulse laser for PIV measurements and the latest in timing and waveform generation. There is also a state-of-the art rheometer and facilities for measuring surface tension and contact angles. In addition, there is access to a wide range of fluid equipment for generating controlled flow fields, such as a micro-wind tunnel for droplet studies, a optical cell for examining crystal growth on the surface, 'glass' rock for examining oil recovery and a range of droplet generation techniques, but also great flexibility in building custom apparatus that captures the essence of industrial processes.
For our computational work, we use and develop various methods encapsulated in both custom-written in-house codes and commercial software such as COMSOL Multiphysics, FLUENT and FLOW-3D. In addition to various flow solver codes based on finite element, finite volume and finite difference methods, we have a rapidly developing lattice Boltzmann capability, particularly for multiphase flow simulations. This allows us to run large-scale parallel computations on high-performance computing facilities such as the University’s Advanced Research Computing system, and exploit the latest developments in computing using graphical processing units (GPUs).