Computational Modelling Group

A Fast Multipole Method for the Bessel potential

Marc Molinari, Simon Cox (Investigators), Neil O'Brien

The fast multipole method (FMM) proposed by Greengard and Rokhlin provides a method by which the O(N-squared) many-body problem can be reduced to O(N) complexity. In this project, a multipole method is developed to calculate the energy of a system of vortices in a high temperature superconductor, where the many-body interactions give rise to rich and complex physics. The method developed here is suitable for systems where the interactions are governed by a Bessel potential rather than the usual logarithmic potentials occurring in gravitational and electrostatic problems. We derive and apply vectorised forms of the Gegenbauer addition formulae in order to achieve the O(N) scaling associated with fast multipole methods.

A Fortran Based Mesh Viewer

Gabriel Amine-Eddine (Investigator)

During my final year as an undergraduate, I developed a fully functional software program for visualising geometries, grids and grid quality aspects, from a customised CFD software tool. It is designed to be used in conjunction with the HARTREE CFD code, and is currently in use by other fellow researchers within my supervisors team.

Ab initio simulations of chemical reactions on platinum nanoparticles

Chris-Kriton Skylaris (Investigator), Alvaro 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.

Aerofoil noise

Richard Sandberg (Investigator)

High-performance computing is used to identify noise sources on aerofoils.

B-meson coupling with relativistic heavy quarks

Jonathan Flynn (Investigator), Ben Samways, Dirk Broemmel, Patrick Fritzsch

We non-perturbatively compute the coupling between B* and B pi meson states relying on relativistic heavy quarks and domain wall light fermions. The coupling is of importance for an effective description of hadronic heavy meson decays.

Computational Methods for Aircraft Noise Prediction

Gwenael Gabard (Investigator), Albert Prinn

The aim of this project is to develop and test an efficient flow acoustics solver based on the finite element method and the potential flow theory.

Control and Prediction of the Organic Solid State

Richard Boardman

This project aims to produce a computer technology for the prediction of the crystal structure(s) of an organic molecule, that could be used even prior to the synthesis of the compound.

Such a computational study could be done relatively quickly to predict the dangers and opportunities of the solid phases of a molecule under development. Our project will develop the methods of experimental screening for polymorphs and their characterisation, and hence the combination will provide a major new technology for aiding industrial formulation.

Development of a novel Navier-Stokes solver (HiPSTAR)

Richard Sandberg (Investigator)

Development of a highly efficient Navier-Stokes solver for HPC.

Feasibility Study of the Impacts of Proposed Tidal Array Installations in Channel Islands

Luke Blunden (Investigator), William Batten

Open source hydrodynamic modelling software TELEMAC is being used to see whether putting a large number of tidal turbines in the sea near a headland-associated sandbank will affect the feature's long term equilibrium.

Fluid Structure Interactions of Yacht Sails

Stephen Turnock (Investigator), Daniele Trimarchi

The research is the main subject of the PhD topic. It regards the application of fluid structure interaction techniques to the domain of yacht sails simulation

Fundamental Investigations of Cross-Coupled, Particle-Turbulence Interactions using a Pseudo Spectral DNS Code

Gabriel Amine-Eddine (Investigator), John Shrimpton

The behaviour of multiphase flows is of primary importance in many engineering applications. In the past, experimental observations have provided many researchers with the ability to understand and probe the phenomena and physical processes occurring in such flows. With advancements in modern day computational power, we now have the ability to gain an even greater wealth of knowledge, from what used to be a physical experiment, is now a virtual experiment, running across multiple computers in parallel architectures.

In this project, we simulate the full Navier-Stokes equations in a virtual experiment, and resolve to the best of degree, all possible scales of turbulence. We have the capability to track millions of computational particles in conjunction with the turbulence, and if the particles are charged, coupled to the turbulence, or if gravity is in the scenarios, we can examine the complex physical processes that occur in such a flow.

Provision has been made to simulate particles in conjunction with turbulence that has been subjected to deformations due to shear, strain, axi-symmetric contraction or expansion. Advancements in this code are soon to include the transport and coupling of scalar temperature between particles and the turbulence.

Currently, focus is on the coupling behaviour of poly-sized particle with the turbulence, and how such turbulence can be modelled accurately using stochastic Langevin methods.

Gravitational waves from neutron stars

Ian Hawke (Investigator)

Gravitational waves, once detected, will give information about the extremes of space and time. Compact objects such as neutron stars are perfect locations for generating such waves.

Hadronic structure on the computer

Jonathan Flynn (Investigator), Dirk Broemmel, Thomas Rae, Ben Samways

In experiments at the Large Hadron Collider (LHC) at CERN, Geneva, the interactions that occur between the colliding particles (protons in this case) can be factorised into a simple scattering between two constituent particles, called quarks, followed by a hadronisation process, which describes the dynamics of forming the bound proton states. Quarks are particles within the proton that bind to form composite particles (hadrons) such as a proton. The scattering process can be computed relatively easily, but hadronisation is intrinsically non-perturbative and hard to calculate. Lattice QCD (computer simulation of QCD on a discrete space-time lattice) provides our only known first-principles and systematically-improvable method to address problems like hadronisation. This project uses Iridis to extract parton distribution amplitudes which are experimentally inaccessible, but needed to describe the quark structure of hadrons.

Is fine-scale turbulence universal?

Richard Sandberg (Investigator)

Complementary numerical simulations and experiments of various canonical flows will try to answer the question whether fine-scale turbulence is universal.

Jet noise

Richard Sandberg (Investigator), Neil Sandham

Direct numerical simulations are used to investigate jet noise.

Laminar to Turbulent Transition in Hypersonic Flows

Neil Sandham, Heinrich Luedeke

Understanding of laminar to turbulent transition in hypersonic boundary-layer flows is crucial for re-entry vehicle design and optimization. The boundary-layer state directly affects the temperatures on the vehicle surface and its viscous drag. Therefore transition has to be considered to correctly compensate for drag and to properly design the thermal protection system.
For the proposed study, in order to obtain a clear understanding of the transition process, the configuration is kept as simple as possible by varying only a minimum number of parameters affecting transition on a simple test geometry such as a swept ramp at different sweep angles. To investigate the influence of such sweep angles on the transition process in the hypersonic regime, Direct Numerical Simulations (DNS) of the turbulent flow field are carried out on the Iridis cluster.

Life assessment methods for industrial steam turbine blade to disc interfaces

Katherine Soady (Investigator)

This is an EngD project sponsored by E.ON New Build and Technology Ltd. which aims to develop the methods currently implemented in life assessment of industrial steam turbine blade to disc interfaces to take account of the surface treatment process (shot peening) which is applied to component before service and after repair.

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.

Modelling Macro-Nutrient Release & Fate Resulting from Sediment Resuspension in Shelf Seas

Chris Wood

This study involves adapting a previously-published model to take into account the effect resuspension events (both natural and anthropogenic) may have on nutrient dynamics at the sediment-water interface, and hence produce better estimates for the total nutrient budgets for shelf seas.

Molecular Fragments in Inhibitor Design

Jonathan Essex (Investigator), Michael Bodnarchuk

Fragment-Based Drug Discovery (FBDD) has emerged as an important tool in the drug discovery process. Instead of screening entire drug molecules, FBDD screens molecular fragments; constituents which make up drug molecules. A computational approach to identifying fragment binding is currently being sought which also yield binding free energy estimation.

MXL Project

Mark Taylor, Junfen Shi (Investigators)

‘MXL’ is short for “Enhanced patient safety by computational Modelling from clinically available X-rays to minimise the risk of overload and instability for optimised function and Longevity”. This is an international EU-funded project which the Bioengineering Sciences Research Group at Southampton is involved in. For more information, visit http://www.m-x-l.eu

Non-Perturbative Renormalisation on the Lattice

Jonathan Flynn (Investigator), Dirk Broemmel, Thomas Rae

In this project we compute renormalisation factors for various physical observables in a non-perturbative lattice framework. Renormalisation hereby arises due to a fundamental scale dependence of the physical processes.

Numerical Elastic Neutron Stars

Ian Hawke, Ian Jones (Investigators), Andrew Penner

We study the gravitational wave forms that radiate from an asymmetric neutron star using an elasto-hydrodynamic model.

Simulations investigating droplet diameter-charge models, for predicting electrostatically atomized dielectric liquid spray chracteristics

Gabriel Amine-Eddine (Investigator), John Shrimpton

Liquid sprays are atomized using electrostatic methods in many scientific, industrial and engineering applications. Due to jet and droplet breakup mechanisms, these spray plumes contain a range of drop diameters with a range of droplet charges. As a result of space charge repulsion forces between droplets, a wide range of inertial characteristics can be observed. Using an transient charged spray CFD code we have performed simulations to investigate charge-diameter relationship models for predicting the dynamics of poly-disperse and electrostatically charged hydrocarbon sprays.

A numerical procedure has been developed to allow for easy simulation and modelling of electrostatically atomised liquid sprays.

Currently work is underway, to extend the methodology developed in this study towards high-pressure sprays, where secondary atomization plays a dominant role within the spray dynamics and subsequent performance of the spray itself.

Statistical model of the knee

Mark Taylor (Investigator), Francis Galloway, Prasanth Nair

Development of methods for large scale computational testing of a tibial tray incorporating inter-patient variability.

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.

Study of global instability in separated flows at high Mach number

Neil Sandham, Zhiwei Hu (Investigators), Kangping Zhang

Flow instability is observed when extending two-dimensional (2D) stable flow into three-dimensional (3D). Development of instability varies along different spanwise length. Thresholds are also discovered for the flow studied to become instable.

Supersonic axisymmetric wakes

Richard Sandberg (Investigator)

Direct numerical simulations are used to shed more light on structure formation and evolution in supersonic wakes.

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.

The effect of roughness upon turbulent supersonic flows

Neil Sandham (Investigator), Christopher Tyson

Understanding the interaction between surface roughness and supersonic air flows are crucial in the design of high speed vehicles, including space re-entry vehicles. Numerical simulations of these flows has been conducted in order to examine and understand how the surface roughness interacts with high speed flows in terms of drag prediction and heat transfer to the wall surface.

The ONETEP project

Chris-Kriton Skylaris (Investigator), Stephen Fox, Chris Pittock, Alvaro Ruiz-Serrano, Jacek Dziedzic

Program for large-scale quantum mechanical simulations of matter from first principles quantum mechanics. Based on theory and algorithms we have developed for linear-scaling density functional theory calculations on parallel computers.

Transition to turbulence in high-speed boundary layers

Neil Sandham (Investigator), Nicola De Tullio

This work is focused on the numerical simulation of hypersonic transition to turbulence in boundary layers. We use direct numerical simulations of the Navier-Stokes equations to analyse the effects of different flow conditions and external disturbances on the transition process. The main objective is to gain insight into the different aspects of transition to turbulence at high speeds, which can lead to the design of new transition models and transition control techniques for high-speed flows.

Vortices in Spinor Bose-Einstein Condensates

Janne Ruostekoski (Investigator), Justin Lovegrove

We numerically study the effect of spin degrees of freedom on the structure of a vortex in an atomic superfluid. Such objects are of interest as macroscopic examples of quantum phenomena, as well as for their analogies in other fields, such as cosmology and high energy physics.

Water Molecules in Protein Binding Sites

Jonathan Essex (Investigator), Michael Bodnarchuk

Water molecules are commonplace in protein binding sites, although the true location of them can often be hard to predict from crystallographic methods. We are developing tools which enable the location and affinity of water molecules to be found.

Whisky Code

Ian Hawke (Investigator)

A 3D finite volume code for simulating compact relativistic hydrodynamics.

Wind direction effects on urban flows

Zheng-Tong Xie, Ian Castro (Investigators), Jean Claus

Numerical simulations of turbulent air flow are conducted on Iridis to investigate the effects of different wind directions on the flow within and above an urban-like canopy.