Marie Curie Early Stage Training Fellowships

The CFD Centre currently runs the "COFLUIDS" Early stage Training (EST) project providing training for 468 person months for early stage researchers from Europe and beyond. Details of the project and the fellows are here.

The goals of CFD are to be able to accurately predict fluid flow, heat transfer and chemical reactions in complex systems, which involve one or all of these phenomena.

Presently, CFD is being increasingly employed by many industries either to reduce manufacturing design cycles or to provide an insight into existing technologies so that they may be analysed and improved. Examples of such industries include power generation, aerospace, process industries, automotive, chemical engineering and construction.

As a design tool, CFD presently sits behind experimental analysis due to the fact that CFD does not produce absolute results. The reason for this is that the numerical methods, which govern the solutions in a CFD problem, rely on several modelling assumptions that may not have been validated to a satisfactory level. However, CFD presently offers itself as a powerful design tool and even more so in the future because:

(a) Dangerous or expensive trial and error experiments can be simulated and design parameters observed prior to any physical prototype being constructed;
(b) Computers are becoming even more powerful and less expensive, thus allowing larger CFD simulations to be calculated, or more detailed simulations of present CFD problems;
(c) The numerical schemes and physical models that are the building blocks of CFD are continually improving.
(d) If a CFD model can be established yielding accurate results on one particular design, then the model can be used as a tool of prediction for that design under many different operating conditions.

Activities and Interests

Brief synopses of areas of interest can be found below, or use the quicklinks to the right. Individual research projects can be found on the Current Projects page, and past projects can be located in the Archives section of this site.

Advanced Wind Turbine Technology

Wind is one of the most abundant renewable energy resources in the world. Advanced wind turbine technology has been explored with great interest recently for both scientific research and commercial effects. At the CFD Centre, in close collaboration with academia and industry, advanced computational fluid dynamics techniques have been used to perform cutting edge research in wind turbine aerodynamics. Recent focus has been in the development of high efficiency, low noise and flexible small to medium sized wind turbines for urban and building environments. Novel ideas have been investigated for overall turbine design through theoretical and experimental study to enable high performance of the turbine across a wide range of wind speed.

CFD is gaining popularity within the Bio-Chemical and Medical Science world. The CFD centre is working in close collaboration with the Silesian University of Technology in using CFD to investigate all the major physical phenomena taking place inside an infant incubator. Combined heat and mass flow processes are analyzed to help design more efficient and reliable medical equipment.

The Volume of Fluid (VOF) formulation can be used to model stratified/free-surface flows as it relies on the fact that two or more fluids (or phases) are not interpenetrating. The CFD centre has been directly involved in explaining events that led to the tragic Air France Concorde disaster that took place in July 2000. Flying rubber from a burst tyre led to a ruptured fuel tank on the underside of the left wing. The emerging fuel flow characteristics were modelled using FLUENT’s VOF model and it was found that a flame was able to stabilise under the wing from a recirculating air zone created within the landing gear bay.

High temperature Solid Oxide Fuel Cells (SOFC) are the most efficient devices for converting hydrocarbon fuels into electricity and can drastically reduce the greenhouse emissions in power plants by using a SOFC and gas turbine hybrid system. The CFD Centre has worked on the development of fuel cell predictive capability for Solid Oxide Fuel Cells (SOFC) and Proton Exchange Membrane Fuel Cells (PEMFC) using CFD technology.

CFD can be used to predict species concentrations within extremely hostile environments where experimental sampling may not be practical. The requirement of a modern gas turbine aero-engine is for reduced emissions of pollutants to meet both civil legislation and military aircraft plume invisibility needs. Sophisticated combustion models have been developed that allow for accurate predictions of important intermediate species which can be used to accurately predict pollutant formation.

The bombardier beetle illustrates a combustion process that takes place in nature that may be applicable to the re-ignition of aircraft and land based gas turbines. An intriguing pressure relief induced steam explosion technique is involved.

Airflows over hills and mountains generate atmospheric turbulence and eddies which cause wind hazards, not only over the mountains but also particularly in the lee. Researchers in the CFD Centre are responsible for the development of new turbulence forecasting and warning models. These are actively used by the Met Office for forecasting in the Falkland Islands and for airfields in Eastern England. The modelling is particularly challenging because of the need to incorporate near-real-time data from atmospheric observing systems and to produce results quickly enough for the warnings to influence planning decisions.

EHL relates to the branch of tribology concerned with the separation by a lubricant film of two bodies in relative motion and under a sufficiently high applied load to cause them to deform. Examples include journal bearings, gear teeth and other engine components. These, normally rigid bodies, deform elastically under the very high operating pressures (commonly up to 3 GPa). It is important to be able to understand and predict the performance of lubricants under their often-extreme working conditions in order to achieve efficiency (generally reduced friction) and durability of the machine components. These calculations are also used in the development of new lubricants with desired physical properties.

Many fluid flow problems contain local solution features that exhibit much smaller length and time scales than others. In the development of CFD software this is typically accounted for through the use of adaptivity in space and time, respectively. Some of the major challenges that are faced by software developers include how to implement this adaptivity and how to control it.

There is a strong research interest in cirrus clouds including both mid-latitude and tropical anvil outflows. Inter-comparisons of cirrus models show that there is huge variability in predictions from different models. The environment centre’s involvement in the GCSS inter-comparison is directed towards resolving this. Current research focuses on understanding the effects of aerosols such as mineral dust on the evolution of tropical anvils to background cirrus using Crystal-Face observations.

Whilst direct formulations consist of determining the effect of a given cause, in inverse formulations the situation is completely or partially reversed. Typical practical applications where inverse problems arise are flows in porous media, heat conduction in materials, tomographic scans of objects, thermal barrier coatings, heat exchangers, corrosion, aerosols, elasicity, acoustics, etc. The objectives are to investigate the existence, uniqueness and stability of the solution to the problem that mathematically models a physical phenomenon under investigation, and to develop new convergent, stable and robust algorithms for obtaining the desired solution.

Many fluid flow problems contain local solution features that exhibit much smaller length and time scales than others. In the development of CFD software this is typically accounted for through the use of adaptivity in space and time, respectively. Some of the major challenges that are faced by software developers include how to implement this adaptivity and how to control it.

Although the flow of water in the natural environment may seem more simple than the study of combustion or other applications of CFD, the large size of rivers and their complex boundary conditions actually make representation in a numerical model an interesting problem. Recent work at Leeds has focused on trying to improve the representation of boundary conditions in these models.

Rather than using steady-state simulation methods, much of the more recent work has been based upon a technique called Large-Eddy Simulation, where one can look at transient flow behaviour, such as the development of vortices at the confluence of two stream tributaries.