Computational Modelling Group

Ab initio simulations of chemical reactions on platinum nanoparticles

Chris-Kriton Skylaris (Investigator), Álvaro Ruiz-Serrano, Peter Cherry

•Use first principles calculations to study the relationship between shape and size of nanoparticle and the oxygen adsorption energy.

• Investigate the effect of high oxygen coverage on the catalytic activity of the nanoparticles.

Advanced modelling for two-phase reacting flow

Edward Richardson (Investigator)

Engine designers want computer programs to help them invent ways to use less fuel and produce less pollution. This research aims to provide an accurate and practical model for the injection and combustion of liquid fuel blends.

Can the principle of Maximum Entropy Production be used to predict the steady states of a Rayleigh-Bernard convective system?

Kevin Oliver, Iain Weaver, James Dyke (Investigators)

The principle of Maximum Entropy Production (MEP) has been successfully used to reproduce the steady states of a range of non-equilibrium systems. Here we investigate MEP and maximum heat flux extremum principles directly via the simulation of a Rayleigh-Bérnard convective system implemented as a lattice gas model.

Chaotic Analysis of Partial Discharge

Paul Lewin (Investigator), Lyuboslav Petrov

The deterministic character of PD pulses predicted by theory has been shown to be existent for certain PD events. Finding characteristic patterns in phase space enables field-data PD detection with high reliability.

Development of wide-ranging functionality in ONETEP

Chris-Kriton Skylaris (Investigator), Jacek Dziedzic

ONETEP is at the cutting edge of developments in first principles calculations. However, while the fundamental difficulties of performing accurate first-principles calculations with linear-scaling cost have been solved, only a small core of functionality is currently available in ONETEP which prevents its wide application. In this collaborative project between three Universities, the original developers of ONETEP will lead an ambitious workplan whereby the functionality of the code will be rapidly and significantly enriched.

Direct Numerical Simulations of transsonic turbine tip gap flow

Richard Sandberg (Investigator)

Direct Numerical Simulations are conducted of the transsonic flow through the tip gap at real engine conditions.

Investigation of gas adsorption of metal-organic frameworks using quantum mechanics and Monte Carlo simulation

Jia Huo (Investigator)

Metal organic frameworks (MOFs) has received much attention in the field of gas storage/separation, catalysis, etc, due to their highly ordered porosity, high surface area, multi functionality, chemically talorability and high loading of meta sites. Experimental method has contributed to these areas, but there are still plenty of problems not solved solely from experiment, including investigation of mechanism of adsorption and screening MOFs for target-specific applications.  In this project, we plan to use quantum mechanics and Monte Carlo simulation to investigate the various guest adsorption properties on MOFs to screen the substrates catalysed by active sites within MOFs and the influence of transition metal sites of MOFs on gas adsorption for design of MOFs with high gas storage capacity.

Large-Scale Quantum Chemistry Simulations of Organic Photovoltaics

Chris-Kriton Skylaris (Investigator), Gabriele Boschetto

The aim of this project is to use first principles quantum mechanical calculations to provide a detailed atomic-level understanding of OPV materials and models of bulk heterojunctions on a far larger scale than possible before by using the ONETEP program for linear-scaling first principles quantum mechanical calculations.

Magnon-Driven Domain-Wall Dynamics in the presence of Dzyaloshinskii-Moriya Interaction

Hans Fangohr (Investigator), Weiwei Wang

The domain wall motion induced by spin waves (magnons) in the presence of Dzyaloshinskii-Moriya Interaction is studied in this project.

Miscible multiphase systems with phase transition

Andrea Boghi

We aim to develop the computational model for the miscible displacement of liquid occupying a porous bulk, as, for instance, in the processes of vegetable solvent extraction, soil remediation or enhanced oil recovery. All these process includes the dissolution of solute and the displacement of solution from porous media. The focus of our current research work is, therefore, twofold: (i) to develop and verify a theoretical model for an evolving miscible displacement, by taking into account dynamic surface tension and mass diffusion through the interphase boundary, and (ii) to provide a model for the solute/solvent displacement from the porous volume.

On the applicability of nonlinear timeseries methods for partial discharge analysis

Paul Lewin (Investigator), Lyuboslav Petrov

The governing processes of Partial Discharge (PD)
phenomena trigger aperiodic chains of events resulting in ’ap-
parently’ stochastic data, for which the widely adopted analysis
methodology is of statistical nature. However, it can be shown,
that nonlinear analysis methods can prove more adequate in
detecting certain trends and patterns in complex PD timeseries.
In this work, the application of nonlinear invariants and phase
space methods for PD analysis are discussed and potential pitfalls
are identified. Unsupervised statistical inference techniques based
on the use of surrogate data sets are proposed and employed for
the purpose of testing the applicability of nonlinear algorithms
and methods. The Generalized Hurst Exponent and Lempel Ziv
Complexity are used for finding the location of the system under
test on the spectrum between determinism and stochasticity. The
algorithms are found to have strong classification abilities at
discerning between surrogates and original point series, giving
motivation for further investigations.

SAVE: Solent Achieving Value through Efficiency

Patrick James, Ben Anderson (Investigators), Luke Blunden

Analysis of 15 minute electricity consumption and 10 second instantaneous power data from 4,000+ households in the Solent region collected over 3 years of a randomised control trial study.

Scalability of Energy Efficient Routing Algorithms in Wireless Sensor Networks

Geoff Merrett (Investigator), Davide Zilli

This project compares two broad classes of routing algorithms for Wireless Sensor Networks, message flooding and single path, by means of a simulation model. In particular, we want to understand how the two scale in terms of energy efficiency on large networks of sensors.

Simulations of Magnetic Skyrmions

Hans Fangohr (Investigator), Ryan Pepper

The manipulation of magnetic skyrmions could prove to be a useful technique for storing data on an unprecedented density scale. In this project we seek to better understand their properties and ways to control them.

Stability of chiral structures in magnetic nanodisks

Hans Fangohr, Weiwei Wang (Investigators), David Cortes

This project is aimed to study the stability of skyrmionic and helical equilibrium states in magnetic nanodisks, using computational simulations.

Stratified combustion physics and modelling

Edward Richardson (Investigator)

Full-resolution simulation data for turbulent combustion are used to investigate the fundamental impact, and practical modelling, of fuel-air stratification.

Sustainable domain-specific software generation tools for extremely parallel particle-based simulations

Chris-Kriton Skylaris (Investigator)

A range of particle based methods (PBM) are currently used to simulate materials in chemistry, engineering, physics and biophysics. The 4 types of PBM considered directly in the proposed are molecular dynamics (MD), the ONETEP quantum mechanics-based program, discrete element modelling (DEM), and smoothed particle hydrodynamics (SPH).
The overall research objective is to develop a sustainable tool that will deliver, in the future, cutting edge research applicable to applications ranging from dam engineering to atomistic drug design.

TEDx: Closing the Loop: Entropy Accounting for a Sustainable World

Stuart Bartlett (Investigator)

This is a TEDx talk that I gave on some ideas I've had about the large-scale thermodynamic organisation of life on Earth. While these ideas probably aren't new, I believe they can teach us something about the way in which we think about energy and the 'consumption' of goods and energy.

The Maximum Entropy Production Principle and Natural Convection

Seth Bullock, James Dyke (Investigators), Stuart Bartlett

In this project I wanted to perform some tests of the so-called Maximum Entropy Production Principle (MEPP) in the context of buoyancy-driven convection in a system with negative feedback boundary conditions.

Unsteady Aerodynamics of Wings in Extreme Conditions

Charles Badoe (Investigator), Neil Sandham, Zheng-Tong Xie

Sizing of civil aircraft is dictated by extreme loads experienced at the limits of flight envelope, for example during gust, turbulence or low speed manoeuvre. The project aims to understand the unsteady aerodynamic behaviour of wings in extreme conditions involving heaving motions near stall.

Using MEP to determine parameter values of ocean and atmosphere diffusivity

Kevin Oliver, James Dyke (Investigators), Maike Sonnewald

Entropy budgets can potentially offer new and valuable insights into the dissipation of energy in the ocean system. Specifically, if one assumes the Earth system maximises the dissipation of energy, one can use this as a guiding principle maximising the internal entropy production. In this study, resultant temperature distributions from a four box ocean-atmosphere-ice model are used to assess to what extent such considerations could ameliorate the need for tuning parameter values associated with oceanic and atmospheric diffusivity. Results from a standard implementation with fixed, empirically determined, parameters were compared to one where the maximum entropy production principle is applied to determine the value of oceanic and atmospheric diffusivity parameters. These methods have been successfully applied to cloud fraction and convection in the atmosphere.

The MEP principle suggested using diffusivity values of 3.3×1014 W K ?1 and 3.2×1014 W K ?1
for the ocean and atmosphere respectively, where the empirical values were 2.0 × 1014 W K ?1
and 1.0 × 1014 W K ?1 . The oceanic temperatures of the MEP implementation were 3 and -1oC
away the high and low latitude observed ocean temperatures respectively, while the empirical
implementation was -5 and 3oC away, largely within the observational standard deviation of
8 and 2? C respectively. For the atmospheric values, MEP implementation was 3W m?2 away
from the high latitude observed value, while the empirical implementation was 6W m?2 away,
both within the standard deviation of 13.2W m?2 . However, in the low latitudes this reverses,
with the empirical implementation being only -16W m?2 off while the MEP implementation
is -21W m?2 off. However, both figures are outside the range of the standard deviation of
4.2W m?2 . Overall, both methods were found to be very close to oceanic observations. This
confirms that in the model used, the assumption of maximal dissipation of energy is reasonable.

Furthermore, the nature of the landscape of internal entropy production created by the
oceanic and atmospheric diffusivity was found to be fairly smooth, with non-linearities mainly
coming from ice albedo. Assuming the Earth system is in a state of maximal energy dissipa-
tion, applying the MEP principle successfully may depend on such a smooth, easily optimisable
landscape. Thus, the successful application of the MEP principle could be much more difficult
if attempting to aid parametrisation in more detailed ocean models, as these are likely to have
internal entropy production landscapes with local maxima. Nevertheless, results presented
are very promising, and encourage further exploration of to what extent this principle could
be applied to ameliorate the need for tuning parameters in light of lacking information.

µ-VIS Computed Tomography Centre

Ian Sinclair, Richard Boardman, Dmitry Grinev, Philipp Thurner, Simon Cox, Jeremy Frey, Mark Spearing, Kenji Takeda (Investigators)

A dedicated centre for computed tomography (CT) at Southampton, providing complete support for 3D imaging science, serving Engineering, Biomedical, Environmental and Archaeological Sciences. The centre encompasses five complementary scanning systems supporting resolutions down to 200nm and imaging volumes in excess of one metre: from a matchstick to a tree trunk, from an ant's wing to a gas turbine blade.