Computational Modelling Group

A step toward establishing minimum requirement for CFD modelling of dispersion from floating roof tanks

Zheng-Tong Xie, Ian Castro (Investigators)

It is of great importance to estimate an emission flux (due to leaking from an oil tank) from near field wake, which requires a better understanding of vortex shedding from the tank, in particularly in how the low frequency motion behaves. Large-eddy simulation approaches embedded in up-to-date CFD package will be used for this purpose. This project has a strong link with Concawe and U Surrey.

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.

CFD for urban environments

Zheng-Tong Xie, Ian Castro (Investigators), Venkata Boppana

As part of the NERC’s National Centre for Atmospheric Science, we are continuing on the modeling of wind flows around buildings and through streets, and the consequent dispersion of pollutants and heat transfer.
In collaboration with CD-adapco, one of the ‘big three’ CFD code vendors.

Complexity in Modelling Electric Marine Propulsive Devices

Suleiman Sharkh, Neil Bressloff, Hans Fangohr (Investigators), Aleksander Dubas

This project involves the simulation of turbulent flow around a marine rim-driven thruster and the complex interaction of flow features involved through computational fluid dynamics.

Development of a novel Navier-Stokes solver (HiPSTAR)

Richard Sandberg (Investigator)

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

Evaluation of Vortex Shedding of Slender Structures using LES Techniques

Zheng-Tong Xie, Ian Castro (Investigators), Steven Daniels

Vortex shedding is a critical design consideration for slender structures such as long-span bridges, high-rise buildings and tele-communication masts. It can create large responses at relatively low wind speeds, leading to serviceability and fatigue concerns.

Since vortex shedding is highly sensitive to the precise shape of the object, there are no established codes or standards that provide adequate evaluation of vortex shedding risks.

The aim of this project is to develop a novel computational approach (based on Large Eddy Simulation, implemented in OpenFoam) that will be available for use by Arup on relevant bridge and building projects. It is anticipated that this tool will be used in early stages of a project to assess vortex shedding risks, which may be confirmed through wind tunnel testing at later stages

Flow and sedimentation processes in submarine meandering channels

Stephen Darby (Investigator)

The overall aim of this project is to generate a step-change in our understanding of the interactions between flow,
morphology & sedimentology within an active submarine channel fed by saline density currents. This central aim will be addressed through a combination of field measurements and innovative numerical modelling of gravity current morphodynamics

Fluid Loads and Motions of Damaged Ships

Dominic Hudson, Ming-yi Tan (Investigators), Christian Wood, James Underwood, Adam Sobey

An area of research currently of interest in the marine industry is the effect of damage on ship structures. Research into the behaviour of damaged ships began in the mid nineties as a result of Ro-Ro disasters (e.g. Estonia in 1994). Due to the way the Estonia sank early research mainly focused on transient behaviour immediately after the damage takes place, the prediction of capsize, and of large lateral motions. Further research efforts, headed by the UK MoD, began following an incident where HMS Nottingham ran aground tearing a 50m hole from bow to bridge, flooding five compartments and almost causing the ship to sink just off Lord Howe Island in 2002. This project intends to answer the following questions:
“For a given amount of underwater damage (e.g. collision or torpedo/mine hit), what will be the progressive damage spread if the ship travels at ‘x’ knots? OR for a given amount of underwater damage, what is the maximum speed at which the ship can travel without causing additional damage?”

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

High-resolution shock-capturing (HRSC) methods for elastic matter in general relativity

Carsten Gundlach, Ian Hawke (Investigators)

We are designing HRSC methods for numerical simulation of elastic matter coupled to general relativity and later magnetic fields, with the ultimate aim of simulating old neutron stars, which have elastic crusts.

Hybrid RANS/LES methods

Richard Sandberg (Investigator), Markus Weinmann

Novel hybrid RANS/LES methods are developed for more accurate and efficient simulation of flow over complex geometries.

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.

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.

Mixed FEM-particle method for nonlinear fluid-structure interaction problems, with applications to maritime engineering

Kamal Djidjeli (Investigator)

Simulating fluid-structure interaction problems involving large flow motions and deformations using particle methods.

Modelling power output and wake effects in tidal stream turbine arrays

William Batten (Investigator), Matthew Harrison, Luke Blunden

The PhD research is regards the investigation of modelling techniques for simplifying turbine simulation so that models of large arrays can be investigated.

Multi-objective design optimisation of coronary stents

Neil Bressloff, Georges Limbert (Investigators), Sanjay Pant

Stents are tubular type scaffolds that are deployed (using an inflatable balloon on a catheter), most commonly to recover the shape of narrowed (diseased) arterial segments. Despite the widespread clinical use of stents in cardiovascular intervention, the presence of such devices can cause adverse responses leading to fatality or to the need for further treatment. The most common unwanted responses of inflammation are in-stent restenosis and thrombosis. Such adverse biological responses in a stented artery are influenced by many factors, including the design of the stent. This project aims at using multi-objective optimisation techniques to find an optimum family of coronary stents which are more resistant to the processes of in-stent restenosis (IR) and stent thrombosis (ST).

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.

Numerical investigation of the true sources of jet noise

Anurag Agarwal (Investigator), Samuel Sinayoko

Aircraft noise severely impacts the quality of life of people living close to airports. Noise generation by aircrafts is especially large during take-off. Jet noise is the dominant noise source during take-off. It is produced by the high speed flow generated by the engine. However, the actual source of sound remains unknown. A deeper understanding of the sources of jet noise is need to be able to reduce the noise. The aim of this project is to implement a innovative method that would allow to identify the sources of jet noise.

Performance improvement in kinetic energy converters though fluid separation

William Batten (Investigator), Tom Blackmore, Luke Blunden

The PhD research is regards the investigation of the effect of flow separators in confined tidal channels to improve performance of tidal stream turbines.

Prediction of Hydrodynamic Characteristics of Planing Hulls using CFD

Kamal Djidjeli (Investigator)

Performance prediction is an important part of vessel design. Common methods used for predicting planing hull performance include empirical equations and model tests. Model tests are usually expensive, while empirical equations are often applicable to similar hull types. In this work, CFD is used as an alternative prediction tool for high speed planing vessels.

Prediction of orifice flow flooding rates through generic orifices

Dominic Hudson, Ming-yi Tan (Investigators), Christian Wood, Adam Sobey

This presearch concentrates on the modelling of compartment flooding rates following the occurrence of damage in a ship's side shell. Typical state of the art flooding models use Torricelli’s formula to calculate flooding rates using a constant co-efficient of discharge (Cd). Based on Bernoulli’s theorem, turbulence and viscosity effects are not included using a Cd independent of damage shape or size. Previous work indicates that this assumption over-simplifies the problem to an extent where the flooding rates used for calculation are in error. This project will use CFD validated by experiment to calculate flooding rates for a large number of cases from which a 'krigged' response surface will be generated. Validity of the subsequent response surface will be interrogated.

Real-time CFD for helicopter flight simulation

Kenji Takeda (Investigator), James Kenny

Project aims to show how real-time computational fluid dynamics (CFD) could be used to improve the realism of helicopter flight simulators.

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.

Stochastic computational methods for aero-acoustics

Gwenael Gabard (Investigator), Martina Dieste

Stochastic methods are used to synthesize a turbulent flow which is then used to model the sound radiated by an airfoil interacting with this turbulence. This approach is faster than performing a complete simulation of the flow field.

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.

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.

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.

Wave-based discontinuous Galerkin methods

Gwenael Gabard (Investigator), Greg Kennedy

Wave-based computational methods are developed to model sound propagation in moving inhomogeneous media.

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.

Wind Turbine Blade Flow in Abnormal Environments

Zheng-Tong Xie (Investigator), Yusik Kim

Large wind turbines are being installed throughout UK and often in regions with complex meteorology and/or topography (e.g. involving wind gusts, turbulence, icing), which affect turbine performance (energy output, noise emission etc), life expectancy and safety. It is very expensive to conduct experiments to study such problems. This proposal suggests, firstly, an LES study of low-Re flows around an oscillating airfoil, to investigate the transition, separation, vortex shedding and dynamic stall behaviour. Secondly, a combined LES-RANS approach (with, e.g., a transitional RANS model in the near wall region) will be carefully designed (using our recently developed efficient turbulence generator at the interface between LES and RANS) and validated against low-Re results.