Wave propagation

Waves are disturbances that propagate through space and time. Examples include mechanical waves in solid and fluids (water waves, sound and vibrations), electromagnetic waves (light, radio waves, etc.), gravitational waves. This topic covers any work aiming to understand and/or predict the interference between multiple waves, scattering by obstacles, and refraction by inhomogeneities. Applications are found in many areas of science and engineering, for instance astrophysics, biomedical applications, acoustical engineering, ship science, etc. For more information see http://en.wikipedia.org/wiki/Wave

For queries about this topic, contact Gwenael Gabard.

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Projects

All-Optical Phase Regeneration of Fiber Optic Communication Signals

Peter Horak (Investigator), Graham Hesketh

All-optical phase regeneration uses a process known as four-wave mixing in a nonlinear optical fiber to carefully mix light with a communication signal in such a way that it cancels transmission noise in the the signals phase, increasing the distance over which the signal can be transmitted. New regenerator designs are presented that suppress phase to amplitude noise conversion and performance is simulated using a supercomputer to assist experimental investigation.

Centre for Doctoral Training in Next Generation Computational Modelling

Hans Fangohr, Ian Hawke, Peter Horak (Investigators), Susanne Ufermann Fangohr, Thorsten Wittemeier, Kieran Selvon, Alvaro Perez-Diaz, David Lusher, Ashley Setter, Emanuele Zappia, Hossam Ragheb, Ryan Pepper, Stephen Gow, Jan Kamenik, Paul Chambers, Robert Entwistle, Rory Brown, Joshua Greenhalgh, James Harrison, Jonathon Waters, Ioannis Begleris, Craig Rafter

The £10million Centre for Doctoral Training was launched in November 2013 and is jointly funded by EPSRC, the University of Southampton, and its partners.

The NGCM brings together world-class simulation modelling research activities from across the University of Southampton and hosts a 4-year doctoral training programme that is the first of its kind in the UK.

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.

Continuously Tunable Optical Buffer

Peter Horak (Investigator)

The project aims to design, fabricate and test a novel integrated all-optical buffer device that is based on MEMS technology and provides a continuously tunable delay for optical pulses over a broad wavelength region. Such a device could play a crucial role in future packet-switched optical networks, photonic integrated circuits and coherent light based applications such as optically steered phase array antennas, LIDAR and optical coherence tomography.

This EPSRC funded project is a collaboration between the Optoelectronics Research Centre, Southampton, and University College London.

Dynamag: computational magnonics

Hans Fangohr, Atul Bhaskar (Investigators), Matteo Franchin, Andreas Knittel

Analytical treatment of long range magneto-dipole interactions is a bottle-neck of magnonics and more generally of the theory of spin waves in non-uniform media. This project develops a theoretical framework for analysis of magnonic phenomena in magnetic nano-structures, including isolated nano-elements, arrays of those, and extended magnonic crystals. The DYNAMAG project is funded by the EU FP7 and the DST of India.

How sensitive is ocean model utility to resolution?

Kevin Oliver (Investigator), Maike Sonnewald

One of the most intriguing problems in recent ocean modeling research is the impact of varying model resolution on model accuracy. Increasing model resolution one includes more of the important processes. However, the increase in accuracy with resolution is unlikely to be linear. Thus, as computational cost increases with resolution, a critical assessment of achieved benefits is prudent. Here we analyse a suite of realistic and compatible global ocean model runs from coarse (1o, ORCA1), eddy-permitting (1/4o, ORCA025) and eddy resolving (1/12o, ORCA12) resolutions. Comparisons of steric height variability (varSH) highlight changes in ocean density structure, revealing impacts on mechanisms such as downwelling and eddy energy dissipation. We assess vertical variability using the covariace of the deep and shallow varSH. Together with assessing isopycnal movements, we demonstrate the influence of deep baroclinic modes and regions where the barotropic flow sheds eddies. Significant changes in the deepwater formation and dispersion both in the Arctic and Antarctic are found between resolutions. The varSH increased from ORCA1 to ORCA025 and ORCA12, particularily in the Southern Ocean and Western Boundary Currents. However, there is no significant covariance between the surface and deep in ORCA1, while ORCA025 and ORCA12 show significant covariance, implying an important missing energy pathway in ORCA1. Comparing ORCA025 and ORCA12 we see significant differences in eddy energy dissipation. We assess the impact of varying model resolution on the mean flow, discussing implications to dissipation pathways on model accuracy, with reference to stochastic parameterisation schemes.

Investigation of acoustic radiation forces on micro-particles and cells in ultrasonic particle manipulation

Martyn Hill (Investigator), Puja Mishra

A Finite Element model is developed to investigate the force generated on a particle of arbitrary geometry and composition in a sound field. The model overcame the drawbacks of existing analytical solutions of size restriction and provided the flexibility of particle representation. This suggested useful results on shape dependency, effect of elasticity of particle and dominancy of nucleus in a cell in estimating the force on a single particle.

Optical Characterisation of Black Silicon for Photovoltaics Using the Finite Element Method

Jack Tyson (Investigator)

Here we present a novel method of simulating the reflectance spectra of black silicon solar cells using the finite element method. Designed in COMSOL Multiphysics is a new set of algorithm-controlled-geometries rendering a vast array of different structural permutations of silicon nanowires. Our model focused on the variation of this geometry within customisable predefined conditions in large output quantities, collated and averaged to reliably determine the reflectance of an entire black silicon solar cell.