ADVANCED COMPUTER MODELS FOR COMPRESSIBLE TURBULENT MIXING
Atomic Weapons Establishment/Cranfield University
The science and engineering of nuclear weapons is among the most contentious in the sector, but for those that work in this part of the industry, the challenges are both daunting and fascinating.
At the Atomic Weapons Establishment at Aldermaston, researchers are attempting to establish exactly what happens at the centre of a nuclear explosion, purely by simulation — a technique that could also have implications for both future power generation and medicine.
David Youngs of AWE is working with Dimitris Drikakis of Cranfield University on simulating the mixing of fluids caused by shock waves. This is an intrinsic part of a fusion explosion — a small implosion forces the fusion fuel to compress and this triggers the larger explosion. It is also at the heart of inertial confinement, one of the competing techniques for power generation by fusion.
The fluid dynamics of shock-wave mixing are extremely complex, with two different phenomena interacting to cause turbulence in the mixture of fluids that reduces the heating of the fusion-fuel gases during the implosion; this inhibits the final explosion.
Youngs and Drikakis have devised a three-dimensional computer simulation to calculate from first principles how an inward-travelling shockwave induces mixing. This, they say, is a vital tool for investigating the physics of this complex situation, and can also be useful in designing medical techniques that use imploding bubbles, such as shockwave chemotherapy or therapeutic ultrasound to destroy kidney stones.
COLLABORATION FOR SPACE EXPLORATION
Magna Parva and University of Leicester
After centuries of wondering and decades of investigating, it is still not clear if there is or ever was life on Mars. Europe’s ExoMars mission, scheduled to take off in 2018, aims to answer many outstanding questions, using a rover designed to search for the signatures of life while also investigating Martian geology.
One of the devices on board, the LifeMarker chip, is the result of a collaboration between Magna Parva, a space science and engineering company based near Loughborough, and the Space Research Centre at the University of Leicester.
The two organisations have collaborated before, notably on an optics system for the Mercury probe BepiColombo, but LifeMarker is notable for its possible spin-off applications in medicine, defence and agriculture. It is designed as a complete lab in a box, using immunoassay techniques to detect the presence of organic molecules that would indicate life.
The main development of the system was the sample processing set-up, which takes a raw sample of Martian soil, prepares it for analysis using two solvents and a de-salting stage, and injects it onto the immunoassay chips, which test for a variety of compounds.
These chips contain antibodies that bind onto their target compounds; if binding takes place, they activate a fluorescent chemical, the glow of which is detected by optical sensors. The system was designed to fit into the tight size and weight constraints of the ExoMars Rover and to operate reliably under the harsh Martian conditions.
University of Southampton, University of Oxford, Imperial College, University of Bristol and BAE Systems
As automated systems become more complex, they are being built up from other automated modules, which have their own sensors of different types, decision-making routines and communications channels. Some modules are said to be’visiting’ rather than being designed as part of the whole system, such as aircraft on airport taxiways. The ALADDIN project aims to find new ways to make such systems work.
The situations the project will tackle include: the co-ordination of police, fire brigades and ambulances in a city-scale emergency; the management of the evacuation of a burning building or ship in distress; and the task of bringing together information from multiple sources, probably owned and operated by different organisations, to predict the weather within a local area — in this case the Southampton area.
The ALADDIN project involves a collaboration between organisations in Italy, the US, Spain and Canada, but perhaps its strongest aspect is that, rather than devising new sensors and communications devices, it attempts to make better use of existing hardware, especially when hardware is operated by several users in situations where there is uncertainty. It is finding applications in port management, weapons allocation and in the UK’s Americas Cup challenge.