IC Engines Control and Emissions
Fluid Mechanics in Process Metallurgy
Modelling of Advanced Power Generation Plant
Professor J.E. Ffowcs Williams
Professor A.P. Dowling
Dr N. Peake
In order to meet ever-increasingly stringent emission requirements, combustors are being designed to operate lean in a premixed mode. Although this is beneficial as far as reducing NOX is concerned, it has the disadvantage that premixed flames are particularly susceptible to thermoacoustic oscillations(A24) and many premixed systems have experienced structural damage caused by combustion instability. Our research is aimed at enabling aero-engines, industrial gas turbines and power stations to operate stably with low chemical pollutants. A premixed ducted flame provides a suitable test case on which to develop theoretical approaches. Our work involves low order modelling(A23) and computational fluid dynamics CFD(A13). The extension of these ideas to the combustors of industrial gas turbines is well-advanced(A25) and measurements on a half-scale industrial burner are providing important insight into the dynamic processes. It is not only premixed systems that undergo combustion instabilities and CFD is being used to understand the self-excited oscillations that occur in aeroengines at idle due to the slow evaporation of liquid fuel droplets(A72). The combustion instability work is well funded with support from EPSRC, the EU and industry, particularly Rolls-Royce and Hitachi.
We are also investigating novel ways of controlling these damaging oscillations(A26). We have demonstrated the control of a combustion oscillation through a suitably phased unsteady addition of fuel(A22). Current work in this area includes the theoretical development of control strategies(A25) and a major experiment on active control of a gas-fuelled lean premixed combustor. It is also possible to eliminate instability by increasing the passive absorption within a combustor. In collaboration with Rolls-Royce and Kawasaki Heavy Industries, we are seeking to improve the understanding and enhance the performance of acoustic absorbers for use in combustors for the next generation of supersonic aircraft.
Tyre noise is also a focus of research in the department. A combined approach involving mathematical modelling, numerical simulations and experiment is being used to provide a better understanding of the mechanisms governing tyre/road noise generation. The ultimate aim is to enable quiet tyres to be designed. The work is funded by EPSRC and is being carried out in collaboration with Dunlop Tyres Ltd, Rover Cars and the Transport Research Laboratory (TRL).
Flow noise and aeroacoustics is a continuing research interest over a wide range of practical conditions. For example, the hydrodynamic forces on towed underwater systems can cause self-excited oscillations. We are studying a particular configuration that highlights the flow/flexible surface interactions on offshore oil/gas pipe-lines as they are being towed into position. We are seeking to understand and eliminate the coupled flow/structure instabilities which cause severe practical problems for the industry.
Expertise in the Department in acoustics, aerodynamics and turbomachinery is being combined to investigate helicopter noise. The work is funded by EPSRC and is being carried out in collaboration with GKN Westland and Thomson-Marconi Sonar Systems Ltd. When a helicopter is in forward flight, patches of supersonic flow occur near the rotor blades and influence the character and amplitude of the noise field. We are making use of CFD with high resolution shock capturing techniques to calculate this flow field, placing particular emphasis on simple models that describe and explain the dynamic changes in the acoustic sources in flight. An extension of the acoustic analogy will be used to predict the far field sound.
The neuromechanical interactions involved in human snoring and its avoidance(A31) is also a continuing research activity as is the aeroacoustics of general fluid-structure interactions(A27).
Research aimed at understanding acoustic resonances driven by vortex shedding in rotor-stator interactions in turbomachines is sponsored by Rolls-Royce and has provided designers with a useful predictive capability(A68,A69). Our studies of aeroengine noise continue, concentrating recently on the interaction between a blade row and the unsteady flow(A58) as a source of noise. Aircraft manufacturers are also looking at the benefits that might come from `scarfing' the intakes to aeroengines(A34).
Sound has many features in common with the weak instabilities that grow into turbulence and they are a continuing source of research interest. The absolute instability(A52) of a flow over a flexible surface(A59) has been analysed in a situation relevant to underwater systems and results have been presented on absolute instabilities of wake flows(A65).
Dr R.S. Cant
Research in computational combustion continues to develop as part of the activity of the Computational Fluid Dynamics (CFD) Laboratory, run collectively by Prof. W.N. Dawes, Dr A.M. Savill and Dr R.S. Cant. Combustion remains extremely important(A36,A37) as a means of producing energy on demand for all manner of applications, from electricity generation through transport to domestic and industrial heating. At the same time, environmental concerns are leading to increasingly severe legislative controls on permitted levels of pollutant emissions from combustion systems, and this is leading to new thinking on burner, combustor and engine design.
The work in computational combustion covers a broad range of modelling(A53,A54,A62,A64,A70,A71) and numerical approaches to the subject(A10,A11,A12). Fundamental investigations on flame-turbulence interaction are carried out using Direct Numerical Simulation (DNS) and the results are fed into the development of new modelling using both the novel technique of Large Eddy Simulation (LES) and the more traditional approach of Reynolds-Averaged Navier-Stokes (RANS) simulation. A broad range of industrial problems have been tackled using these methods.
In DNS, the governing equations are solved directly, using highly accurate numerical schemes, and without any form of modelling. Two EPSRC-funded projects are currently under way in this area. The first is aimed at using massively-parallel computers such as the Hitachi SR2201 in Cambridge and the Cray T3E in Manchester to generate large amounts of statistical data on turbulent flame structure for use in model development for LES and RANS computations(A32). This project involves some of the largest computations of turbulent premixed flames carried out worldwide to date(A33). The second DNS project is concerned mainly with the development of the underlying computational science, such as novel numerical techniques involving wavelet-based discretisation schemes(A60,A61), new methods of treating complex chemistry and new formulations for boundary conditions.
Good progress is being made in the development of LES techniques for application to industrial problems in combustion. The advantages of LES are considerable in terms of physical accuracy, especially for unsteady flows. Increases of computer power together with new and more efficient solution methods are bringing the technology within reach for practical problems. Projects in this area are sponsored by Alstom Gas Turbines and involve research into LES sub-grid scale modelling of turbulent reaction rates and of turbulent transport of heat and mass. The modelling is designed to be robust
as well as accurate and the model development process is making extensive use of DNS data. The initial application is to lean premixed gas turbine combustors where thermoacoustic phenomena involving strongly unsteady flow and combustion are proving to be a significant obstacle to technological progress. The use of LES is intended to assist designers who are seeking to avoid such difficulties.
Computational combustion for industry mainly involves the use of RANS simulation for reasons of computational cost, and the development of advanced modelling for RANS-based applications is continuing(A1). Data from both DNS and LES is proving invaluable in the development process. Several CFD codes are available for RANS work, including a 2D structured-grid pressure-correction solver as well as an unstructured adaptive 3D code that is able to handle industrial geometries of arbitrary complexity using locally-developed CAD interfaces. Areas of industrial interest include direct-injection spark-ignition engines sponsored by Ricardo Consulting Engineers; large-scale accidental explosions in offshore process plant(A9) sponsored by BP, Shell, BG Research and Technology, EPSRC and HSE; detonation initiation sponsored by EPSRC; and gas turbine combustors(A13) sponsored by Hitachi Europe and Rolls-Royce.
Dr N. Collings
The engine group continues a thriving activity in emissions and engine control. Our use of fast emissions sampling equipment has given fresh insights into the operation of catalysts under transient conditions, and the same instrumentation has been used to improve our predictive abilities in modelling in-cylinder emissions generation(A7,A28). New opportunities for engine control when switching between high efficiency and high power conditions have been demonstrated(A49).
New activities are under way in the areas of high frequency response measurements of carbon dioxide and carbon monoxide, and a significant activity in the area of particle emissions from internal combustion engines has begun. The continuing support of the Ford Motor Company in this work is gratefully acknowledged.
Dr P.A. Davidson
Fluid mechanics plays a critical rôle in the production and casting of metals(A16,A17). For example, aluminium is produced by electrolysis in large reduction cells. This process is highly energy intensive, requiring around
30 MWatt hrs to produce one tonne of semi-finished product. Indeed, worldwide, electrolysis cells consume
around 2% of all generated electricity. Yet the bulk of the energy expended in reduction cells is not required for electrolysis, but rather is lost in resistive heating of the electrolyte. Attempts to increase the efficiency of these cells, by reducing the volume of electrolyte, have been fundamentally limited by the appearance of an instability which manifests itself as a sloshing of the electrolyte and is directly triggered by the reduction in electrolyte volume. The fundamental nature of these instabilities is just beginning to be understood(A50) and we have now identified a means of suppressing the instability(A15).
In the casting industry, on the other hand, fluid flow plays a critical rôle in determining the metallurgical structure; quality and surface finish of an ingot. There are vigorous turbulent flows within the liquid zone of a partially solidified ingot, driven by thermal buoyancy, by compositional variations throughout the melt, and by the flow of liquid into the mould. This flow is the dominant mechanism for transporting heat, chemical species and crystal fragments within the liquid metal pool. Modest changes in the structure of this flow can produce a large difference in the distribution of impurities and dendrite size and morphology within the final ingot(A56).
Research Council awards in this area are supporting our work on: the influence of fluid flow on macrosegregation in aluminium ingots(A56); the control of high-temperature titanium jets in spray-forming processes(A63); and the fluid mechanics of vacuum-arc remelting(A19,A20,A35).
Dr P.A. Davidson
Dr T. Alboussière
Dr M.D. Cowley
Magnetic fields can be used to levitate, pump and stir liquid metals, to suppress natural convection, and to reorganise the structure of turbulent flows. We are actively involved in all of these areas. In MHD turbulence we are examining the rôle of magnetic fields in preferentially suppressing transverse components of angular momentum(A15). This leads to a strongly anisotropic turbulent structure, reminiscent of turbulence in stratified or rotating media.
This may be quantified using a variant of the classic Kolmogorov/Landau model for the decay of conventional, isotropic turbulence. We are also examining the behaviour of quasi-two-dimensional turbulence, induced by very intense magnetic fields. Here direct numerical simulation of two-dimensional turbulence is planned, funded by Fluent Europe. This has applications in MHD and geophysics.
Work on buoyancy-driven flows and its implication for materials processing has been continuing, as has the collaboration with the two French laboratories, Madylam and CEA-CEREM at Grenoble. A review of the use of magnetic fields in crystal growth has been published(A29). Studies of how a steady magnetic field may lessen the influence of convection, either of thermal or of solute origin, in the measurement of diffusivities have been undertaken analytically; the predictions have been confirmed by numerical work and also validated by the experimental results of our colleagues in France(A2,A3,A39).
An analysis of the stability of Hartmann layers has been published(A51). This type of layer commonly occurs at solid boundaries to magnetohydrodynamic flows when there is a magnetic field component perpendicular to the boundary. Its influence on the whole flow field is of importance in crystal-growth and metallurgical applications. The work on Hartmann layers has been extended by a study of their turbulent behaviour and good agreement with early experimental results has been achieved. This may affect the study of quasi-2D turbulence(A4,A21) if the Hartmann layer is no longer laminar. Parallel-wall layers, where there is no normal component of the magnetic field at the boundary, have also been studied by an analytical method which puts more emphasis on the physical mechanisms than has been customary in the past(A14).
Dr G.T. Parks
Dr J.D. Lewins
Longstanding research in collaboration with North Carolina State University continued into the optimisation of in-core fuel cycles (reload design) for Pressurised Water Reactors. A major review of the field was published(A66). A new method for solving multi-objective reload design problems based on the Simulated Annealing algorithm was developed(A57). Collaboration with Imperial College and British Energy investigating the potential of Tabu Search for in-core fuel cycle optimisation continued(A8,A57).
A paper concerning the behaviour of charged particles in varying magnetic fields with relevance to magnetic confinement fusion was published(A41). Research into the use of variational techniques in the solution by Monte Carlo simulation of neutron transport equations yielded further results(A5,A6). Parallel work on the development of a variational principle for Markov, semi-Markov and pseudo-Markov systems for Monte Carlo dynamic reliability studies continued(A38,A46,A47,A48).
Two notes concerning the teaching of thermodynamics were published(A40,A44) and several articles were written for the Journal of the Institution of Nuclear Engineers(A42,A43,A45).
Dr A.J. Organ
The 25cm3 nitrogen-charged Ross drive engine has been commissioned, instrumented and tested. A novel vertical installation with the weight of the dynamometer counterbalanced by a filar suspension totally eliminates trunnion friction and allows accurate determination of output torque. Power output remains below the design value, but thermal efficiency peaks at precisely the rpm (1100) corresponding to peak efficiency rpm (2000) of the helium-charged engine from which the design was scaled. The improved accuracy of torque measurement has permitted extension of the rpm range over which internal pumping loss can be inferred with the engine motored. The similarity parameter for thermal short has been established and corroborated by the tests(A55).
Design of the hair drier engine has been completed and the majority of components manufactured. The project calls for a high efficiency fan, and this has been tackled by converting the classic analysis of the minimum induced loss propeller to the static thrust case.
Professor J.B. Young
Three quite different aspects of particle and droplet transport in two-phase flows have provided recent
research interest. In wet-steam turbines and other naturally nucleated flows there are vast numbers of submicrometre droplets which interact with the turbulence and migrate to solid surfaces. The dominant transport mechanism is turbophoresis, the migration of particles in the direction of decreasing turbulence levels. A new theory of turbulent transport has been developed and is being applied to the motion of such droplets in boundary layers.
For larger particles of a few micrometres diameter, transport involves the combined effects of particle slip due to streamline curvature and turbulent migration. A project, supported by PowerGen, has been investigating the complex processes by which ash particles in coal-fired gas turbines are deposited on the blades. As the blade surfaces are cooled, thermophoresis also plays an important role. A computer code for predicting particle transport in cascade flows using an Eulerian-Eulerian formulation has been developed. The scheme is stable for a wide range of Stokes numbers and is effective in capturing concentration discontinuities at the edge of particle-free `shadow zones'.
Droplets which are tens or hundreds of micrometres in diameter pay little attention to the turbulence but have their own special problems because of the possibility of distortion and fragmentation. A project funded jointly by Rolls-Royce and the Civil Aviation Authority is investigating the effects on performance of the ingestion of tropical rain into aero-engines. Apart from modelling the deposition on the blading, the project is investigating the movement of water films on the blades and casing, and the breakup of droplets re-entrained into the flow from the trailing edges.
Professor J.B. Young
The global power generation industry is currently undergoing a technical revolution due to the widespread availability of natural gas, the rapid development of industrial gas turbines of all sizes, and the deregulation of electricity generation. Many new types of high efficiency power plant are currently under investigation by industry and university. A collaboration between Cambridge and Newcastle Universities, and the Rolls-Royce Advanced Engineering Centre has been initiated to establish a power systems modelling group to investigate novel possibilities for environmentally clean power generation. An initial project has undertaken a study of the cooling of gas turbine blades resulting in improved models for the cooling losses. Further work will investigate some possibilities for the capture of carbon dioxide from power plants(A30).
A1. Abu-Orf, G.M., Cant, R.S. Reaction rate modelling for premixed turbulent combustion. International Flame Research Foundation (IFRF) and Combustion Institute Joint Flame Days, St Peters Port, Guernsey (October 1998).
A2. Alboussière, T., Garandet, J.P., Lehmann, J.P., Moreau, R. Convective effects in the measurement of diffusivities and thermotransport coefficients. Liquid metal alloys and the use of a magnetic field. Entropie, 218, 59-62 (1999).
A3. Alboussière, T., Garandet, J.P., Lehmann, P., Moreau, R. Measurement of solute diffusivity in electrically conducting liquids. Transfer Phenomena in Magnetohydrodynamic and Electroconducting Flows: Selected Papers from 3rd International PAMIR Conference, Aussois, France (September 1997); Edited by A. Alemany, P. Marty, J.P. Thibault, chapter 29, 359-372. Fluid Mechanics and Its Applications 51 (Kluwer, 1999). ISBN 0-79-235532-6.
A4. Alboussière, T., Uspenski, V., Moreau, R. Quasi-2D MHD turbulent shear layers. Experimental Thermal and Fluid Science, 20, (1), 19-24 (1999).
A5. Allagi, M.O., Lewins, J.D. Real and virtual sampling in variational processing of stochastic simulation in neutron transport: the one-dimensional rod. Annals of Nuclear Energy, 25, (18), 1521-1542 (1998).
A6. Allagi, M.O., Lewins, J.D. Virtual sampling in variational processing of Monte Carlo simulation in a deep neutron penetration problem. Annals of Nuclear Energy, 26, (7), 611-628 (1999).
A7. Ball, J.K., Stone, C.R., Collings, N. Cycle-by-cycle modelling of NO formation and comparison with experimental data. Proceedings of the Institution of Mechanical Engineers, Part D, Journal of Automobile Engineering, 213, (D2), 175-189 (1999).
A8. Ben Hmaida, I.A., Carter, J.N., de Oliveira, C.R.E., Goddard, A.J.H., Parks, G.T. Nuclear in-core fuel management optimisation using the Tabu search method. Proceedings, International Conference on Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications, Madrid, Spain, 2, 1658-1666 (September 1999).
A9. Birkby, P., Cant, R.S., Savill, A.M. The application of a laminar flamelet model to confined explosion hazards. Proceedings, 17th International Symposium on Dynamics of Explosions and Reactive Systems, Heidelberg, Germany (August 1999).
A10. Bray, K.N.C. Challenges in turbulent combustion. In: Introduction to Turbulent Combustion. VKI Lecture Series 1999-04 (Von Karman Institute for Fluid Dynamics, March 1999).
A11. Bray, K.N.C., Champion, M., Libby, P.A. Premixed combustion in laminar Couette flow: extinction and mass burning rate. Combustion and Flame, 118, (4), 633-650 (1999).
A12. Bray, K.N.C., Champion, M., Libby, P.A. Premixed flames in stagnating turbulence part III, the mean velocities and pressure and the Damköhler number. Combustion and Flame, 112, (4), 635-653 (1998).
A13. Brookes, S.J., Cant, R.S., Dowling, A.P. Modelling combustion instabilities using computational fluid dynamics. Proceedings, ASME International Gas Turbine and Aeroengine Congress and Exhibition, Indianapolis, IN, USA, ASME Paper 99-GT-112 (June 1999).
A14. Cowley, M.D. Suppression of buoyant motion in melts. Proceedings, 4th International Congress on Industrial and Applied Mathematics, Edinburgh (July 1999).
A15. Davidson, P.A. Magnetic damping of jets vortices and turbulence. Fluid Flow Phenomena in Metals Processing: Symposium at 128th TMS Annual Meeting, San Diego, CA, USA (February/March 1999); Edited by N. El-Kaddah, D.G.C. Robertson, S.T. Johansen, V.R. Voller, 49-56 (Minerals, Metals and Materials Society (TMS), Warrendale, PA, USA, 1999). ISBN 0873394240.
A16. Davidson, P.A. Magnetohydrodynamics in materials processing. Annual Review of Fluid Mechanics, 31,
A17. Davidson, P.A. The material benefits of casting and refining using magnetic fields. Materials World, 6, (11),
675-678 (November 1998).
A18. Davidson, P.A., Graham, W.R., O'Brien, H.L. Instability mechanisms in aluminium reduction cells. Light Metals 1999: presented at 128th TMS Annual Meeting, San Diego, CA, USA (February/March 1999); Edited by C.E. Eckert, 327-331 (Minerals, Metals and Materials Society (TMS), Warrendale, PA, USA, 1999). ISBN 0873394259.
A19. Davidson, P.A., Kinnear, D., Lingwood, R.J., Short, D.J., He, X. The role of Ekman pumping and the dominance of swirl in confined flows driven by Lorentz forces. European Journal of Mechanics-B/Fluids, 18, (4), 693-711 (1999).
A20. Davidson, P.A., Kinnear, D., Short, D. The role of Ekman pumping in confined MHD flows. Progress in Fluid Flow Research: Turbulence and Applied MHD; Edited by H. Branover, Y. Unger, 621-636. Progress in Astronautics and Aeronautics 182 (AIAA, 1999). ISBN 1563472848.
A21. Delannoy, Y., Pascal, B., AlboussiÈre, T., Uspenski, V., Moreau, R. Quasi-two-dimensional turbulence in MHD shear flows: The "MATUR" experiment and simulations. Transfer Phenomena in Magnetohydrodynamic and Electroconducting Flows: Selected Papers from 3rd International PAMIR Conference, Aussois, France (September 1997); Edited by A. Alemany, P. Marty, J.P. Thibault, chapter 29, 93-106. Fluid Mechanics and Its Applications 51 (Kluwer, 1999). ISBN 0-79-235532-6.
A22. Dowling, A.P. Active control of combustion oscillations. Proceedings, 30th AIAA Fluid Dynamics Conference, Norfolk, VA, USA, AIAA Paper 99-3571 (June/July 1999).
A23. Dowling, A.P. A kinematic model of a ducted flame. Journal of Fluid Mechanics, 394, 51-72 (1999).
A24. Dowling, A.P. Thermoacoustic instability. Proceedings, 6th International Congress on Sound and Vibration, Copenhagen, Denmark, 3277-3292 (July 1999).
A25. Dowling, A.P., Hubbard, S. Instability in lean premixed combustors. IMechE Seminar, Turbulent Combustion of Gases and Liquids - Leading Edge Technologies, Lincoln (December 1998).
A26. Evesque, S., Chu, Y.C., Dowling, A.P., Glover, K. Feedback control of a premixed ducted flame. Proceedings, 14th International Symposium on Air Breathing Engines, Florence, Italy, Paper IS-194 (September 1999).
A27. Ffowcs Williams, J.E. Book review: Acoustics of Fluid-Structure Interactions by M.S. Howe, Cambridge University Press, 1998. Journal of Fluid Mechanics, 391, 377-380 (1999).
A28. Ford, R.G., Collings, N. Measurement of residual gas fraction using a fast response NO sensor. Electronic Engine Controls 1999: Sensors, Actuators and Development Tools: Papers, 1999 SAE International Congress and Exposition, Detroit, MI, USA, SAE Technical Paper 1999-01-0208. Society of Automotive Engineers SP-1418 (March 1999). ISBN 0768003504.
A29. Garandet, J.P., Alboussière, T. Bridgeman growth: modelling and experiments. Progress in Crystal Growth and Characterization of Materials, 38, (1), 73-132 (1999).
A30. Horlock, J.H., Young, J.B., Manfrida, G. The rational efficiency of fossil-fuel power plants. Proceedings, Symposium on Thermodynamics, at 1998 ASME International Mechanical Engineering Congress and Exposition, Anaheim, CA, USA, 235-242. ASME AES Publication 38 (November 1998).
A31. Huang, L., Ffowcs Williams, J.E. Neuromechanical interaction in human snoring and upper airway obstruction. Journal of Applied Physiology, 86, (6), 1759-1763 (1999).
A32. Jenkins, K.W., Bushe, W.K., Leboucher, L.L., Cant, R.S. Direct numerical simulation of turbulent flames. In: High Performance Computing; Edited by R.J. Allan, M.F. Guest, A.D. Simpson, D.S. Henty, D.A. Nicole, 395-405 (Kluwer Academic, New York, 1999).
A33. Jenkins, K.W., Cant, R.S. Direct numerical simulation of turbulent flame kernels. Proceedings, 2nd AFOSR (US Air Force Office of Scientific Research) International Conference on DNS (Direct Numerical Simulation) and LES (Large Eddy Simulation), New Brunswick, NJ, USA (June 1999).
A34. Keith, G.M., Peake, N. The effects of scarfing and curved lip geometry on the radiation from an intake. 5th AIAA/CEAS Aeroacoustics Conference and Exhibit, Bellvue, WA, USA, AIAA Paper 99-1947 (May 1999).
A35. Kinnear, D., Davidson, P.A. Energy constraints in forced recirculating MHD flow. Journal of Fluid Mechanics, 375, 319-343 (1998).
A36. Kioni, P.N., Bray, K.N.C., Greenhalgh, D.A., Rogg, B. Experimental and numerical studies of a triple flame. Combustion and Flame, 116, (1/2), 192-206 (1999).
A37. Kostiuk, L.W., Shepherd, I.G., Bray, KN.C. Experimental study of premixed turbulent combustion in opposed streams. Part III - spatial structure of flames. Combustion and Flame, 118, (1/2), 129-139 (1999).
A38. Labeau, P.E., Lewins, J.D. On the feasibility of variationally processed calculations in dynamic reliability. Safety and Reliability: 10th European Conference, ESREL '99, Munich, Germany (September 1999); Edited by G.I. Schueller, P. Kafka, 2, 987-992 (A.A. Balkema, Rotterdam, 1999).
A39. Lehmann, J.P., Alboussière, T., Moreau, R., Uspenski, V. MHD control of convection applied to chemical diffusivities measurements. Journal de Chimie Physique et de Physico Chimie Biologique, 96, 1105-1110 (1999).
A40. Lewins, J.D. Beyond the boundary layers: the Blasius paradox. International Journal of Mechanical Engineering Education, 25, (1), 55-61 (1999).
A41. Lewins, J.D. Conservation of angular `momentum' in a varying magnetic field. Fusion Technology, 34, (3), Part 1, 241-253 (1998).
A42. Lewins, J.D. Letters: Comment on history of fast reactors. Nuclear Engineer, 40, (3), 99 (1999).
A43. Lewins, J.D. Obituaries: Professor Jack Edwards. Nuclear Engineer, 40, (3), 80 (1999).
A44. Lewins, J.D. Optimizing cascades of endo-reversible heat engines. International Journal of Mechanical Engineering Education, 27, (2), 91-101 (1999).
A45. Lewins, J.D. Reminiscences: An explosive situation. Nuclear Engineer, 40, (5), 166 (1999).
A46. Lewins, J.D. Variational principle for pseudo-Markov systems. Progress in Nuclear Energy, 34, (4), 361-375 (1999).
A47. LEWINS, J.D., BECKER, M. (Editors). Advances in Nuclear Science and Technology, volume 26 (Plenum, 1999). ISBN 0306461102.
A48. Lewins, J.D., Chang, M-C. Monte Carlo variational processing for semi-Markov systems. Safety and Reliability: 10th European Conference, ESREL '99, Munich, Germany (September 1999); Edited by G.I. Schueller, P. Kafka, 2, 921-927 (A.A. Balkema, Rotterdam, 1999).
A49. Li, J., Collings, N. A semi-empirical model of fuel transport in intake manifolds of SI engines and its application in transient conditions. Society of Automotive Engineers International Congress and Exposition, Detroit, MI, USA, SAE Technical Paper 1999-01-1314 (March 1999).
A50. Lindsay, R.I., Davidson, P.A. The physical nature of reduction cell instabilities. Progress in Fluid Flow Research: Turbulence and Applied MHD; Edited by H. Branover, Y. Unger, 659-670. Progress in Astronautics and Aeronautics 182 (AIAA, 1999). ISBN 1563472848.
A51. Lingwood, R.J., Alboussière, T. On the stability of the Hartmann layer. Physics of Fluids, 11, (8), 2058-2068 (1999).
A52. Lingwood, R.J., Peake, N. On the causal behaviour of flow over an elastic wall. Journal of Fluid Mechanics, 396, 319-344 (1999).
A53. Louch, D.S., Bray, K.N.C. Vorticity and scalar transport in premixed turbulent combustion. 27th Symposium (International) on Combustion, Pittsburg, PA, USA (August 1998), 1, 801-810 (Combustion Institute, 1998).
A54. Luo, K.H., Bray, K.N.C. Combustion-induced pressure effects in supersonic diffusion flames. 27th Symposium (International) on Combustion, Pittsburg, PA, USA (August 1998), 2, 2165-2171 (Combustion Institute, 1998).
A55. Organ, A.J. The miniature, reversed Stirling cycle cryo-cooler: integrated simulation of performance. Cryogenics, 39, (3), 253-266 (1999).
A56. Paireau, O., Davidson, P.A., AlboussiÈre, T. Natural convection in an aluminium ingot. Fluid Flow Phenomena in Metals Processing: Symposium at 128th TMS Annual Meeting, San Diego, CA, USA (February/March 1999); Edited by N. El-Kaddah, D.G.C. Robertson, S.T. Johansen, V.R. Voller, 387-393 (Minerals, Metals and Materials Society (TMS), Warrendale, PA, USA, 1999). ISBN 0873394240.
A57. Parks, G.T., Suppapitnarm, A. Multiobjective optimization of PWR reload core designs using simulated annealing. Proceedings, International Conference on Mathematics and Computation, Reactor Physics and Environmental Analysis in Nuclear Applications, Madrid, Spain, 2, 1435-1444 (September 1999).
A58. Peake, N., Evers, I. Turbulence-cascade interaction with nonuniform mean flow. 5th AIAA/CEAS Aeroacoustics Conference and Exhibit, Bellevue, WA, USA, AIAA Paper 99-1842 (May 1999).
A59. Peake, N., Lingwood, R.J. A causal stability analysis of the boundary layer over a compliant wall. Proceedings, IUTAM Symposium on Laminar-Turbulent Transition, Sedona, AZ, USA (September 1999).
A60. Prosser, R., Cant. R.S. On the use of wavelets in computational combustion. Journal of Computational Physics, 147, (2), 337-361 (1998).
A61. Prosser, R., Cant, R.S. Wavelets in the direct numerical simulation of combustion. Poster presentation, Royal Society Discussion Meeting on Wavelets: the Key to Intermittent Information, London (February 1999).
A62. Reveillon, J., Bray, K.N.C., Vervisch, I. DNS study of spray vaporisation and turbulent micromixing. American Institute of Aeronautics and Astronautics, AIAA Paper 98-1028 (1998).
A63. Short, D.J., Davidson, P.A. An electromagnetic valve for sprayforming and gas atomisation. Fluid Flow Phenomena in Metals Processing: Symposium at 128th TMS Annual Meeting, San Diego, CA, USA (February/March 1999); Edited by N. El-Kaddah, D.G.C. Robertson, S.T. Johansen, V.R. Voller, 607-612 (Minerals, Metals and Materials Society (TMS), Warrendale, PA, USA, 1999). ISBN 0873394240.
A64. Stevens, E.J., Bray, K.N.C., Lecordier, B. Velocity and scalar statistics for premixed turbulent stagnation point flames using PIV. 27th Symposium (International) on Combustion, Pittsburg, PA, USA (August 1998), 1, 949-955 (Combustion Institute, 1998).
A65. Taylor, M.J., Peake, N. The long-time impulse response of compressible swept-wing boundary layers. Journal of Fluid Mechanics, 379, 333-350 (1999).
A66. Taylor, M.J., Peake, N. A note on the absolute instability of wakes. European Journal of Mechanics B - Fluids, 18, (4), 573-579 (1999).
A67. Turinsky, P.J., Parks, G.T. Advances in nuclear fuel management for light water reactors. In: Advances in Nuclear Science and Technology, volume 26; Edited by J.D. Lewins and M. Becker, 137-165 (Plenum, 1999). ISBN 0306461102.
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Last modified: June 2000