Staff publications (SoE)
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Item Open Access Airline Jet Fuel Hedging: Theory and practice(Taylor & Francis, 2006-11) Morrell, Peter; Swan, WilliamMost international airlines hedge fuel costs, but the theoretical justification behind this action is weak. The paper explores the nature and extent of airline fuel hedging and asks why airlines hedge. The availability of hedging instruments is first discussed, with the most liquid markets in crude and exchange traded contracts. Aviation fuel contracts are possible, but with counter-party risk. Most major passenger airlines with sufficient cash and credit now hedge at least part of their future needs. Hedging does protect profits against a sudden upturn in crude prices caused by political and consumer uncertainty leading to slower economic growth. However, if higher oil prices are induced by strong economic growth and oil supply constraints, hedging increases volatility with hedging gains reinforcing improved profits from higher traffic and improved yields. If hedging does not reduce volatility, it may still have an accounting role in moving profits from one time period to another, insure against bankruptcy, and signal the competence of management to investors and other stakeholders.Item Open Access ANASE: measuring aircraft noise annoyance very unreliably.(Blackwell Publishing, 2008-03) Brooker, PeterDoes anyone who lives under a flight-path like aircraft noise? It is a political hot potato as well as a peace-destroyer. Tens of thousands of people will hear the noise from any third runway at Heathrow. So, when a study commissioned by the government claimed that people are becoming less tolerant of aircraft noise, it made highly unpleasant reading for supporters of a third runway. But the Department for Transport rejected the report as unreliable. Peter Brooker senses the vibrations.Item Open Access Aviation and Climate Change: I - UK Airport CO2 Emissions.(UK & International Press, 2009) Brooker, PeterAviation’s contribution to climate change is now a topic of considerable interest. This paper summarises some key facts on airport CO2 emissions, and highlights some policy implications.Item Open Access Aviation and Climate Change: II - Air Traffic Management and Aviation Non-CO2 Issues.(UK & International Press, 2009)Action on climate change is now the subject of worldwide and European legislation. The following explores some of the issues raised for air traffic management (ATM) and aviation ‘Non-CO2’ Issues. A key aim is to examine some widely quoted figures about the size of aviation’s emission effects.Item Open Access Aviation and Climate Change: II – Air Traffic Management and Aviation Non-CO2 Issues.(UK & International Press, 2009) Brooker, PeterAction on climate change is now the subject of worldwide and European legislation. The following explores some of the issues raised for air traffic management (ATM) and aviation ‘Non-CO2 ’ Issues. A key aim is to examine some widely quoted figures about the size of aviation’s emission effects.Item Open Access Cabin Air Sampling Study Functionality Test.(Cranfield University School of Engineering, 2008-01) Muir, Helen; Walton, Christopher; McKeown, RebeccaThe Department for Transport (DFT), on behalf of the Government’s Aviation Health Working Group (AHWG), commissioned Cranfield University to organise, manage and deliver a functionality test of a variety of air sampling devices capable of detecting a wide range of compounds in a cabin air environment. The functionality test was to be the preliminary stage of a major monitoring study of the cabin air environment, which the Department intends to conduct.Item Open Access Combined Stereoscopic Particle Image Velocimetry and Line Integral Convolution Methods: Application to a Sphere Sedimenting Near a Wall in a Non-Newtonian Fluid.(The Visualization Society of Japan, 2005) Lawson, Nicholas J.; Finnis, Mark V.; Tatum, J. A.; Harrison, G. M.The flow fields for a sphere sedimenting through a Newtonian and two non-Newtonian liquids near a wall in a square tank are investigated using 3-D stereoscopic particle image velocimetry (PIV) and line integral convolution (LIC) methods. The PIV data were taken using an angular stereoscopic configuration with tilt and shift arrangements for the Scheimpflug condition and a pair of liquid correction prisms. Data were recorded from planes perpendicular and parallel to the wall for each fluid case over a range of distances from the wall. The PIV and LIC results highlight significant differences in the wake structure for all three cases. Out of plane flow was also found to persist up to two sphere diameters downstream in the wake for all cases.Item Open Access Determination and Applications of Environmental Costs at Different Sized Airports – Aircraft Noise and Engine Emissions.(Springer, 2006-01) Lu, Cherie; Morrell, PeterWith the increasing trend of charging for externalities and the aim of encouraging the sustainable development of the air transport industry, there is a need to evaluate the social costs of these undesirable side effects, mainly aircraft noise and engine emissions, for different airports. The aircraft noise and engine emissions social costs are calculated in monetary terms for five different sized airports, ranging from hub airports to small regional airports. The number of residences within different levels of airport noise contours and the aircraft noise classifications are the main determinants for accessing aircraft noise social costs. The environmental impacts of aircraft engine emissions include both aircraft landing and take-off and 30-minute cruise. The social costs of aircraft emissions vary by engine type and aircraft category, depending on the damage caused by different engine pollutants on the human health, vegetation, materials, aquatic ecosystem and climate. The results indicate that the relationship appears to be curvilinear between environmental costs and the traffic volume of an airport. The results and methodology of environmental cost calculation could be applied to the proposed European wide harmonised noise charges as well as the social cost benefit analysis of airports.Item Open Access Developments in the supply of direct international air services from airports in Scotland.(Elsevier, 2005-07) Pagliari, RomanoScotland's location, limited population size and absence of major base carriers have served to constrain the development of direct international air services. Air service liberalisation has altered the degree to which different segments of the international passenger market are served at each airport. Overall, air service provision has been enhanced by the activities of Ryanair at Prestwick, long-haul airlines operating to Glasgow and the use of regional jets by franchise carriers at Aberdeen and Edinburgh. These initiatives, to a large extent, were as a result of promotional efforts undertaken by the airport operators. The Scottish Executive-administered Interim Route Development Fund has been less effective in this regard.Item Open Access An evaluation of possible EU air transport emissions trading scheme allocation methods(Elsevier Ltd, 2007-11) Morrell, PeterThe European Commission has been requested by member states to study the incorporation of air transport into their existing emissions trading scheme (ETS). Only CO2 is to be included, at least initially. This paper focuses on the method of allocation of emissions permits in the EU context. It has been assumed here that the EU ETS will be applied only to intra-EU flights and that airlines will be the entities selected for implementation. Three UK airlines were selected to evaluate three main types of allocation: grandfathering, auctioning and benchmarking. The airlines were representative of the three major airline business models: network, low-cost carrier and charter/leisure. Based on 2003/2004 aircraft/engine type and operating data, the per passenger impact of each allocation option was analysed for each airline. A new benchmarking approach is proposed that takes into account both the landing and take-off (LTO) cycle and per kilometre emissions: this avoids penalising shorter sector operators and focuses on the damage caused by aircraft and their engines and not on passengers.Item Open Access Finding a good aircraft noise annoyance curve.(Institute of Acoustics, 2008-07) Brooker, PeterThe aim has been to find a good aircraft noise annoyance Dose-Response curve, using practical and robust techniques with the minimum of modelling assumptions. Several socio-economic/industrial and airport operation factors affected Dose-Response data. This includes ‘population sorting’ at higher noise exposure locations and employment connections, which are likely to reduce annoyance reactions at higher Ldn values; and airport modal effects on people’s recent noise exposure experience, which will produce a defective Dose-Response relationship. Simple moving average smoothing of the data is a useful procedure. This enables the construction of synthetic large samples – without curve modelling assumptions. It makes apparent the Dose-Response data’s underlying structure. It is straightforward to fit simple curves to this processed data, and to indicate statistical confidence. Note that the large amount of Dose-Response data available is not sampled from a single curve, but rather from a variety of such curves. The assumption is that there is the same underlying ‘mix’ of characteristics in the future. The analysis has to exclude data from new runways, etc airports. The affected people would be responding to marked Ldn increases over a comparatively short time, not just the actual Ldn at the time of survey. The degree of population sorting is an issue, ie people with high sensitivity moving to a lower noise exposure location.Item Open Access Is it Safe for Me to Fly?(Royal Statistical Society, 2008-09) Brooker, Peter‘Is it Safe for Me to Fly’ seems like a simple question. But who is Me, what is Safe, and why is there a reason for focusing on Fly? Is the underlying question: ‘Are the people responsible doing everything they should to make flying safe?’ Good questions – so what are the answers?Item Open Access Linear quadratic control of plane Poiseuille flow-the transient behaviour.(Taylor and Francis, 2007-12) McKernan, John; Whidborne, James F.; Papadakis, GeorgeThis paper describes the design of optimal linear quadratic controllers for single wavenumber-pair periodic 2-D disturbances in plane Poiseuille flow, and subsequent verification using a finite-volume full Navier-Stokes solver, at both linear and non-linear levels of initial conditions selected to produce the largest linear transient energy growth. For linear magnitude initial conditions, open and closed-loop finite-volume solver results agree well with a linear simulation. Transient energy growth is an important performance measure in fluid flow problems. The controllers reduce the transient energy growth, and the non-linear effects are generally seen to keep energy levels below the scaled linear values, although they do cause instability in one simulation. Comparatively large local quantities of transpiration fluid are required. The modes responsible for the transient energy growth are identified. Modes are shown not to become significantly more orthogonal by the application of control. The synthesis of state estimators is shown to require higher levels of discretiation than the synthesis of state-feedback controllers. A simple tuning of the estimator weights is presented with improved convergence over uniform weights from zero initial estimates.Item Open Access On ice-induced instability in free-surface flows.(Cambridge University Press, 2007-04) Shapiro, Evgeniy; Timoshin, SergeiThe problem of stability of a water-coated ice layer is investigated for a free-surface flow of a thin water film down an inclined plane. An asymptotic (double-deck) theory is developed for a flow with large Reynolds and Froude numbers which is then used to investigate linear two-dimensional, three-dimensional and nonlinear two-dimensional stability characteristics. A new mode of upstream-propagating instability arising from the interaction of the ice surface with the flow is discovered and its properties are investigated. In the linear limit, closed-form expressions for the dispersion relation and neutral curves are obtained for the case of Pr = 1. For the general case, the linear stability problem is solved numerically and the applicability of the solution with Pr = 1 is analysed. Nonlinear double-deck equations are solved with a novel global-marching-type scheme and the effects of nonlinearity are investigated. An explanation of the physical mechanism leading to the upstream propagation of instability waves is provided.Item Open Access Sesar's ATM Target Concept: Keys to sucess.(2008-01) Brooker, PeterThere is often a right time to do things. In the 1570s, Martin Frobisher abandoned his efforts to find the Northwest Passage, but the attempt might well have been successful today. The nature of a problem and the technical tools available to tackle it can change dramatically over time. Is this the right time for radical changes to Air Traffic Management (ATM)? What will be the keys to success? An earlier article in Navigation News (Jan/Feb 2007) examined the USA’s Air Traffic Management (ATM) programme NGATS, now renamed ‘NextGen’. There has recently been important progress in the European analogue to NextGen: SESAR. SESAR is the European ATM modernization programme, focused on 2020. Its first phase is the Definition Phase, which is co-funded by Eurocontrol and the European Commission (Trans European networks). The SESAR Consortium is carrying out the Definition Phase study. The Consortium has about 30 members (eg Air France, BAE Systems) and about 20 associated partners (eg Boeing, Dassault, and European ATM research centres). A major ‘SESAR Deliverable’ was the 162-page ‘ATM Target Concept’, issued in late September 2007. This briefing paper illustrates some of the important features of the Concept, especially where its ‘magic’ might come from to deliver large improvements in performance, and tries to identify key issues in the path to successful implementation. The report’s authors make it very clear that it is a vision not a plan, and certainly not a final blueprint of the future system.Item Open Access Study of jet precession, recirculation and vortex breakdown in turbulent swirling jets using LES.(Elsevier, 2009-06) Ranga Dinesh, K. K. J.; Kirkpatrick, M. P.Large eddy simulations (LES) are used to investigate turbulent isothermal swirling flows with a strong emphasis on vortex breakdown, recirculation and instability behaviour. The Sydney swirl burner configuration is used for all simulated test cases from low to high swirl and Reynolds numbers. The governing equations for continuity and momentum are solved on a structured Cartesian grid, and a Smagorinsky eddy viscosity model with the localised dynamic procedure is used as the sub-grid scale turbulence model. The LES successfully predicts both the upstream first recirculation zone generated by the bluff body and the downstream vortex breakdown bubble. The frequency spectrum indicates the presence of low frequency oscillations and the existence of a central jet precession as observed in experiments. The LES calculations well captured the distinct precession frequencies. The results also highlight the precession mode of instability in the center jet and the oscillations of the central jet precession, which forms a precessing vortex core. The study further highlights the predictive capabilities of LES on unsteady oscillations of turbulent swirling flow fields and provides a good framework for complex instability investigations.Item Open Access A Study of LES Stress and Flux Models Applied to a Buoyant Jet.(Taylor and Francis Ltd, 2005-09-03) Worthy, Jude; Rubini, Philip A.Large eddy simulation (LES) stress and scalar flux subgrid scale models are evaluated in the context of buoyant jets. Eddy viscosity, eddy diffusivity (including formulations of the generalized gradient diffusion hypothesis), “structure” (Bardina and Leonard), mixed, and dynamic models are scrutinized. The performance of the models is examined in terms of the main flow variables and also with respect to the “internal” behavior of the models in terms of the relative contributions to the turbulent kinetic energy budget.