ACARE Taxonomy A common European taxonomy for aeronautical research & technology

Transcription

1 ACARE Taxonomy A common European taxonomy for aeronautical research & technology D.P. Hannessen and J.C. Donker No part of this report may be reproduced and/or disclosed, in any form or by any means without the prior written permission of the owner. Customer: ACARE Contract number: Owner: ACARE Distribution: Limited Classification title: Unclassified January 2003

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3 -3- Summary To provide a support infrastructure for the Advisory Council on Aeronautical Research in Europe (ACARE), the Aeronautical Stakeholders Tools for the European Research Agenda (ASTERA) project was set up. ASTERA contains several work packages. The taxonomy work package describes the identification and definition of a common taxonomy for the European aeronautical community. It consists of an organised listing of research & technology (R&T) related topics within the European aeronautical community. This document is the end result of the taxonomy work package. In it, the project approach is described, as well as the contributors and the end product of the work package, viz. the ACARE taxonomy. The taxonomy lists Research & Technology areas identified by a group of representatives of European aeronautics industries, institutes, and overarching aeronautics organisations. An initial taxonomy was built on a combination of expertise of the representatives and results from earlier similar projects. From this point it has been modified and expanded along new insights resulting from consultations with a Steering Group with representatives from European aeronautics industries, institutes and overarching organisations. The taxonomy is brought to at least one level deeper compared to previous undertakings (e.g. by GARTEUR), thus providing a more complete overview of aeronautics areas as well as a more in-depth view in which areas have been detailed into domains and sub-domains. The ACARE taxonomy will therefore not only serve those on a strategic / management level but should also be functional as a common reference taxonomy to those working in the area of aeronautical research in general.

4 -4- List of abbreviations ACARE AECMA ARDEP ASTERA ATM CIRA DLR EADS EREA GARTEUR NASA NLR ONERA R & T SCITEC SRA Advisory Council on Aeronautical Research in Europe European Association of Aerospace Industries Analysis of Research and Development in EUROCONTROL Programmes Aeronautical Stakeholders Tool for the European Research Agenda Air Traffic Management Centro Italiano Ricerche Aerospaziali (Italian Aerospace Research Centre) Deutsches Zentrum für Luft- und Raumfahrt (German Aerospace Centre) European Aeronautic Defence and Space Company European Research Establishments in Aeronautics Group for Aeronautical Research and Technology in Europe National Aeronautics and Space Administration Nationaal Lucht- en Ruimtevaartlaboratorium (National Aerospace Laboratory) Office National d'etudes et de Recherches Aérospatiales (National office for aerospace research) Research & Technology Science and Technology study Strategic Research Agenda

5 -5- Contents 1 Introduction 7 2 Taxonomy Purpose Approach Organisation Taxonomy rationale ASTERA Taxonomy Taxonomy Areas Taxonomy Domains, sub-domains Taxonomy Area 1: Flight Physics Taxonomy Area 2: Aerostructures Taxonomy Area 3: Propulsions Taxonomy Area 4: Aircraft Avionics, Systems & Equipement Taxonomy Area 5: Flight Mechanics Taxonomy Area 6: Integrated Design & Validation (methods & tools) Taxonomy Aera 7: Air Traffic Management Taxonomy Area 8: Airports Taxonomy Area 9: Human Factors Taxonomy Area 10: Innovative Concepts & Scenarios 83 3 Conclusions & Recommendations 85 4 References 87 (87 pages in total)

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7 -7-1 Introduction In order for Europe to maintain its competitiveness in aviation for the next twenty years, a formation of European stakeholders in aeronautics defined a strategic research agenda (SRA). The SRA is the plan for materialising the Vision 2020 of the European Research Area, and the goals identified by the vision. Those goals are to make Europe the world leader in aeronautics through collaboration, strengthened and guided by a single shared vision. Common mechanisms will be created for research and technological development in the service of a leading-edge sector, symbolising European industrial ingenuity and excellence. The established formation, the Advisory Council for Aeronautics Research in Europe (ACARE), was set up with the aim of developing and maintaining the strategic research agenda for aeronautics in Europe. One of the first ACARE activities was to define the Taxonomy work package as part of the Aeronautical Stakeholders Tools for the European Research Agenda (ASTERA) project. The objective of the ACARE taxonomy work is to achieve the definition of a Europeansupported taxonomy in a relative short period of time. The taxonomy should consist of an organised listing of research & technology (R&T) related topics within the European aeronautical community. A Working Group was set out to identify and define the taxonomy. Each Working Group member obtained information from experts in certain taxonomy areas regarding structure and description. The experts would then formulate a definition including sub-domains. Throughout the process a large Steering Group advised the Working Group. The Steering Group members were representatives from aeronautical industries, technology institutes and Europeanwide aeronautical organisations. With this ensemble difficult issues could be solved with regard to the overall structure of the taxonomy. Through meetings with the Steering Group and through reviews of the taxonomy, a broadly supported taxonomy was created, which is essential if the taxonomy is to be used by a substantial European group of managers and technical staff. Not re-inventing the wheel was a primary issue and the Steering Group took the care to start its work from already well established classifications and build from them. In this document the resulting taxonomy is described, as well as the process via which the taxonomy was defined. This will be done by explaining the purpose of the taxonomy in more detail, in section 2.1. The approach taken for constructing the ACARE taxonomy is described in

8 -8- section 2.2. The taxonomy itself is presented in section 2.3 and will consume the larger part of the document. Chapter 3 contains conclusions and recommendations for the maintenance and accessibility of the taxonomy for a wide European audience.

9 -9-2 Taxonomy 2.1 Purpose The main purpose of the ACARE taxonomy is to provide technological support to the ACARE council by means of a workable definition list concerning aeronautical R&T topics that exist within the different European partners from industries and institutes. This list has to be agreed and used by all stakeholders in the European aeronautical community in order to make correct comparisons and benchmarks of R&T capabilities. Its use will be at the start of the ACARE initiative, providing a terminology base for a common understanding in the ASTERA projects to follow. Therefore the taxonomy will function as one of the first foundations in the implementation of the SRA. The taxonomy is required to be flexible, easy to use for higher-level management purposes and also useable at more detailed levels to compare research activities. 2.2 Approach A consortium consisting of the Netherlands National Aerospace Laboratory NLR, QinetiQ of the UK, and ONERA of France was selected by the ACARE customer to define the ACARE taxonomy in the second half of EUROCONTROL also provided direct support to the consortium. The first phase in the project was to get a clear understanding of what taxonomy approaches existed for aerospace, e.g. at NASA, SCITEC, and EUROCONTROL. Different approaches were found, varying from alphabetical listings of topics to topics that were cross-linked in a matrix form to achieve multiple perspectives. As a second activity, the approach for the ACARE taxonomy was defined to comply with the following requirements and constraints for the taxonomy: - Achieve a common structure and high-level description for European research and technology development, through an organised listing of research & technology (R&T) related topics within the European aeronautical community. - Address the broad range of aeronautical products, technology developments and tools on a manager scale. - Support multiple views for managers and technology people. - Obtain wide guidance via a Steering Committee to enable broad use within the European aeronautical community. - Produce the taxonomy structure and high-level definition in the period August 2002 to December Describe aeronautics topics only; do not describe space-only topics.

10 Support dual use, civilian and military when covering military topics; do not describe military-only topics. This list was specified by the Steering Group together with the customer at the beginning of the project. It was then passed on to all experts within the Working Group s organisations to work with. Because of the timeframe the project was bound by some practical decisions on, for example, the level of detail and the review sessions with all the project members Organisation Within the group of project members, the taxonomy has been constructed by a working-group, which received valuable feedback from a specially formed Steering Group. This Working Group consisted of specialists from three different organisations divided over three countries: ONERA (D. Nouailhas) in France, QinetiQ (B. Spedding) in the United Kingdom and National Aerospace Laboratory NLR (D.P. Hannessen) in the Netherlands. The overall project management was placed at NLR. Onera and NLR being member of the Association of European Research Establishments in Aeronautics (EREA). From the beginning of the project it became clear that in order to achieve maximum agreement on any form of European terminology listing, representatives from all European fields were needed. A Steering Group was formed to provide senior management guidance. The Steering Group was also formed with the goal of representing European industry, (national) technology institutes, and representatives of air transport users. It was formed of the following members (in alphabetical order): - AECMA (A. Swan / L. Bottasso) - Airbus (D. King) - DLR (U. Möller / A. Junior) - EADS (J.L. Galvani) - EUROCONTROL (J.L. Marchand) - NLR (F.J. Abbink) - Rolls Royce (N. Peacock) The Steering Group members provided directions at the beginning of the work, functioned as a sounding board, and provided support for the taxonomy definition through reviews of deliverable items. The Steering Group convened at major milestones in the project to discuss review comments and to set directions for the remainder of the project.

11 Taxonomy rationale In order to get maximum agreement of all stakeholders the ACARE taxonomy has been defined with its future users in mind. First of all these are the members of the ACARE group, but later technical people and sub-level management may also encounter the taxonomy in their work. Therefore, it was decided that the topics chosen in different levels of the taxonomy should be able to be mapped to the topics common to the users working domain. The Steering Group advised to take the previously developed GARTEUR taxonomy as starting point for the Working Group. Then a goal was set to take this GARTEUR taxonomy and complete it and define it at least one level deeper. This led to the agreement of the overall structure of the ACARE taxonomy. The level of detail of the taxonomy was also discussed, for here one could find different approaches as well. The approach was taken to define a relatively small number of research areas, and to detail these further into domains and sub-domains. Existing research domains were carefully studied for areas or domains missing in the GARTEUR taxonomy. The existing research domains are believed to be very useful for facilitating an easy mapping of existing research and technology of particular organisations to the common R&T areas of the ACARE taxonomy. The Working Group constructed a first taxonomy from literature studies and existing taxonomies. ATM related topics, which were not part of the GARTEUR taxonomy, were already defined by EUROCONTROL as part of ARDEP. Since this area fits perfectly into the ACARE taxonomy, it was copied into the ACARE taxonomy without major changes. Since the GARTEUR taxonomy was taken as a baseline, the structure of the ACARE taxonomy is also hierarchical. First there is a top-level of ten so-called main aeronautical areas. These areas are divided into domains. For each domain, a definition is provided. Below each domain follow sub-domains, which are described through the listing of keywords. This will serve as a context boundary in where the domain should be regarded. See the figure below. Using the GARTEUR taxonomy gave an early handle in the beginning. Although it has been changed considerably (e.g. level of detail, areas, domains, etc.) it speeded up the process of focusing on the structure in an early phase. Choosing the matrix format for the taxonomy was also considered, since this would enable different views (application-oriented, technology-oriented, etc.). Although the hierarchical structure led to a number of discussions, the hierarchical approach was maintained to achieve the intended effort and timeframe.

12 -12- Also a matrix was considered by some to be less accessible for a broad audience that a structured hierarchical listing which would create more overview. See the figure below for the hierarchical layout of the taxonomy. Domain 1 Definition Sub-domains Area 1 Domain 2 Definition Sub-domains... Domain 1 Definition ACARE Taxonomy Area 2 Domain 2 Sub-domains Definition Sub-domains Area 10 Figure 2.1. ACARE Taxonomy structure For easy reference, each area and domain is specified by a number of its area, its three-letter abbreviation and its full name. As an example: 211 HAA Helicopter Aero-acoustics In this example the number 211 is constructed of first the number of the area it is placed in, which is two in this case, and its successive number within this area, which is eleven. Experts within the Working Group s organisations provided definitions and the keyword listing for each domain. This process involved sometimes reformulating or altering the area of the domains as reviews showed a better consistent location within the taxonomy. There was no preselected number of domains or sub-domains for each area. The experts within the Working

13 -13- Group organisations were free to define the necessary number of domains and sub-domains themselves. Throughout the process, some areas showed groups of related domains. This brought in the idea of clustering within some areas. During the development it also became clear that some items could fall under more than one area depending on their level of specification. This is not necessarily a problem as long as one instance is the more domain-specific one and the other instance contains the generalised explanation. For example, if an item in the field of support systems is specific enough for area Air Traffic Management its name should clearly mention this (e.g. ATM automated support ). But in the area of Integrated design and Validation there is also need for a more overall explanation, so that will be called Decision Support Systems. A system of cross-referencing between taxonomy entries will help clarify these sorts of relationships. 2.3 ACARE Taxonomy Below is the list of the top-level areas in the taxonomy. These areas are the result of several cycles of evaluation from the Steering Group. The main criteria set for this top level were that there should be enough areas for a reasonable degree of differentiation between them, but that the number of areas should not be unmanageably large. It was agreed that a list of ten areas was compact enough to be easy to use, whilst still encapsulating the main topics of European aeronautics.

14 Taxonomy Areas Taxonomy version: Moderator: National Aerospace Laboratory NLR RESEARCH & TECHNOLOGY AREAS: 1. Flight physics FLP 2. Aerostructures AST 3. Propulsion PRO 4. Aircraft Avionics, Systems & Equipment AVS 5. Flight Mechanics FLM 6. Integrated Design & Validation (methods & tools) IDV 7. Air Traffic Management ATM 8. Airports APT 9. Human Factors HFA 10. Innovative Concepts & scenarios ICS Taxonomy Domains, sub-domains For each of the ten areas, its domain, definitions and sub-domains are listed in the following sub-sections

15 Taxonomy Area 1: Flight Physics 1 FLP FLIGHT PHYSICS 101 CFD Computational Fluid Dynamics 102 UAD Unsteady Aerodynamics Definition: Computational Fluid Dynamics (CFD) consists in the development, validation, and use of software tools for the numerical simulation of fluid flows past aerodynamic vehicles. CFD is a discipline necessitating the knowledge of applied mathematics, fluid dynamics and computer sciences. Different levels of modelling are used for solving the governing partial differential equations of fluid flows (incompressible or compressible, inviscid or viscous...). Physical models have to be validated and calibrated by comparison with experimental data. Geometry of flow domain and boundary and initial conditions must be taken into account properly. Discretised equations are solved through numerical schemes and algorithms aiming at accuracy, efficiency and robustness. The computer codes are run on scalar or parallel computers along the following steps: After the grid generation (or adaptation), the CFD solver is run before post-processing and visualisation of the results. CFD is used for understanding physics by flow ana Sub-domains: 1. Physical modelling (turbulent, reactive flows ) 2. Development of numerical schemes and algorithms 3. Development and production of CFD software 4. Validation of CFD software 5. Grid generation and adaptation 6. High Performance computing (vector and parallel processing) 7. Complex CFD applications Definition: In aerodynamics, unsteady phenomena occur from shock-boundary layer interaction or boundary layer separation, but also are present in the flows around rotating systems. They concern the external aerodynamics of all the vehicles : aircraft, helicopter, projectile and launcher. To answer the purpose of transport aircraft, the aims of studies are guided by the requirement of non separated flow in cruise and some constraints in the flight envelope : buffeting onset, flutter risk, limit cycle oscillation and level and spectral power of the loads on structures. Unsteadiness is an important parameter on the behaviour and the performances of flexible aircraft. For fighters at high angle of attack, separated flows are encountered in air intakes on forebody, wings and afterbody. Thus, hysteresis phenomena of lift coefficient is the characteristic of quick manoeuvres in aerial combat. The aircraft behaviour during flight in turbulence is also an important feature for penetration mission. Airflow around helicopter is of course unsteady due to the relative speed of local flow on the blades during the rotation of the rotor (advancing side and retreating side) and to the cyclic movements of articulated blades. The same kind of unsteady interaction is encountered between propfan and wing of commuters.

16 API Aeronautical Propulsion Integration blades. The same kind of unsteady interaction is encountered between propfan and wing of commuters. The buffeting observed at the base of launchers is created by strong separation of the external flow and interactions with exhaust plume. Internal separation in over-expanded nozzles at the take-off is unsteady and 3D and causes lateral forces beside the thrust. The behaviour in gust and during the activation of control surfaces are important data for the control of the vehicles. Unsteady flows are also encountered in turbomachinery due to the rotation and interactions between the stages. Sub-domains: 1. Computational Fluid Dynamics 2. Wind tunnel testing; Aeroelasticity 3. Flow separation 4. Rotor aerodynamics 5. Buffeting 6. Flutter 7. Shock wave-boundary layer inter-action 8. Buzz 9. Surging 10. Rotating stall Definition: 1. For aircraft, the design of powerplant installation aims to minimise the installation drag by avoiding the separation on the pylon or on the wing in all the flight envelope, particularly at low lift coefficient. New installations are studied in order to reduce the noise, for example by engine location on the upper side of the wing or with semi-buried engines. Experimental tests on models in wind tunnels need to use TPS techniques for simulating the mass flow rate into the nacelle and its effect on the flow around the wing. 2. For rotorcraft, the aims of the studies are to minimise the hub drag and the interaction drag and to reduce the aerodynamic noise. Some works concern the design of air intakes in relation to airflow through the rotor and of the nozzle in order to reduce the heat transfer on the rear part of the fuselage (infrared signature). 3. For airbreathing missile, the air intakes are optimised to take in account some constraints of stealthiness (RCS) and assume a good efficiency at high angle of attack. Some devices are necessary to prevent the separation of the flow on thin lips or in the S-shape diffuser.

17 AFC Airflow control Sub-domains: 1. Computational Fluid Dynamics 2. Wind Tunnel Testing 3. Air intake 4. Nozzle 5. Drag reduction 6. Flow separation 7. Air flow control 8. Infrared Signature 9. Radar signature 10. Noise reduction Definition: In this recent and promising area, a lot of devices are searched to act on the boundary layer, on shockboundary layer interaction, on separation or on vortex development in order to : - reduce the drag by active or passive means; - develop new concepts for improving the behaviour or the control of the aircraft near the limits of the flight envelope or to extend the flight envelope; - minimise the effect of wake behind large aircraft in take-off or landing configurations. The control systems concern civil aircrafts, fighters and rotor blades and can be passive or active. MEMS can also be used. For controlling the boundary layer separation due to shock or adverse pressure gradient, the main devices are vortex generators, bump, cavity (passive control) and fluidic systems (blowing or synthetic jet). To reduce the friction drag of turbulent boundary layer, riblets or MEMS can be used. The delay of the transition location is obtained through laminar flow control techniques. The vortex control is realised by mechanical (leading edge flaps) or pneumatic device (forebody and wing vortices). Trailing edge vortex control can be made with adapted trailing edge flaps. Optimisation of rotor blades is also searched to get less vibration and less noise by means of active control without diminishing aerodynamic efficiency (mechanical or pneumatic system). For stealth subsonic airbreathing missile, control devices are needed to prevent separation of the air flow in the short S duct.

18 HLD High Lift Devices Sub-domains: 1. Computational Fluid Dynamics 2. Wind Tunnel Testing 3. Drag reduction 4. Laminar flow 5. Transition/turbulence 6. MEMS 7. Vortex generator 8. Wing tip device 9. Synthetic jet 10. Blowing flap 11. Bump riblet Definition: Main objectives of the studies related to high lift devices are : - to reduce take-off and landing distances ; - to get simpler and lighter high lift systems (typically 3 airfoils) with the same efficiency than more complex systems ; - to reduce aerodynamic noise. The first topic concerns civil transport and military aircraft. Because the high sweep angle of the wing of supersonic transport and combat aircraft, the leading edge and trailing edge flaps have to be efficient at higher angles of attack for the landing. The multi-surface lifting arrangement is very sensitive to viscous effects due to the very closed interactions between wakes and boundary layers. Specific distributions of the lift along the wing are also studied in order to modify the topology of the vortices in the wake of big aircraft. Sub-domains: 1. Computational Fluid Dynamics 2. Wind Tunnel Testing 3. Multi-surface airfoil 4. Leading edge flap; trailing edge flap 5. Noise reduction 6. Wake vortex 7. Air traffic management 8. Certification Requirements

19 WGD Wing Design Definition: The main objective of the wing design is the minimisation of the drag in cruise conditions : - lift induced drag, through appropriate platform, twist design or through wing tip devices (winglet, wing tip sail, tip turbine, ); - viscous drag, through airfoil section shaping to avoid separation of turbulent boundary layer; - shock wave drag, controlled in order to prevent strong interaction with boundary layer (no separation). On the other hand, improvements are searched on aerodynamic interactions, in particular wing-body, propulsion installation and static margin in order to reduce the trim drag. The wing design uses the last improvements of CFD with numerical optimisation tools and now some multidisciplinary constraints are included in the process. For the design of flexible wing like rotorcraft blade, coupling methods are used where structural deformations are taken in account. In some cases acoustic constraints are also introduced. On missiles, the design of control surfaces is mainly driven by hinge moment constraint. Sub-domains: 1. Computational Fluid Dynamics 2. Wind Tunnel Testing 3. Drag reduction 4. Wing tip device 5. Multidisciplinary optimisation 6. Flexible wing 7. Noise reduction 107 AER Aerodynamics of External and Removable items Definition: The spreading out of landing gears which provokes an increase of the drag and a negative pitching moment which can modify the behaviour of the aircraft and these aerodynamic phenomena have to be taken in account in flight model for the approach phase and take-off. On the other part, the landing gears increase the aerodynamic noise and some solutions are searched to minimise this nuisance. Antenna but also mainly pods are also sources of extra drag and possible aeroelastic problems. The external carriage of stores causes a drag penalty for the aircraft. Fuel tanks (and missiles for military aircraft) dramatically reduce the range of the aircraft and induce modifications of the static margin. At transonic speeds, unstable shock waves are located on stores and can cause damages on control surfaces. Store carriage optimisation aims at reducing drag penalty (conformal pack), flow unsteadiness as well as radar signature. Evaluation of store trajectories during release is needed for flight security.

20 WTT Wind tunnel Testing/Technology Sub-domains: 1. Computational Fluid Dynamics 2. Wind Tunnel Testing 3. Aerodynamic noise 4. Unsteady flow 5. Radar signature 6. Landing Gear 7. Flight / Ground Tests 8. Pod Definition: Wind tunnels are essentially used in R&D to study flow phenomena and to simulate on scaled models the aerodynamics of any aircraft or other aerodynamically relevant object. Geometry, Mach number and Reynolds number are, in that order the main similarity conditions for a precise (nearly exact) simulation. Other conditions may apply (e.g. inertia, real gas...). Depending on what needs to be simulated, numerous (>100) techniques have been developed, some common to most tunnels, some more specific to a certain class of facilities. Sub-domains: 1. Model design/manufacturing: concurrent engineering, from CFD to CAD/CAM, quick prototyping systems. 2. On-line data acquisition/reduction systems: high sampling rates for unsteady flows, handling of large data bases, standardised data presentation. 3. Wind tunnel flow conditioning: flow quality survey/improvement (angularity, turbulence, noise), high Reynolds number simulation (pressure, cryogenics), high enthalpy tunnels. 4. Full or semi-span model common techniques: global & local loads, pressures, boundary layer transition checking, aerodynamic coefficients, buffeting boundaries, visualisations, model support and wall interference correction/reduction. 5. Airframe/propulsion integration: air intakes, nozzles/afterbodies, motorised nacelles, propellers, helicopter rotors, stealth. 6. Flow/surface flow survey: by intrusive and/or non intrusive means. 7. Specific techniques such as : Aeroacoustics, Aeroelasticity/flutter, Jettison (free drop & captive trajectory), Ground effect, Dynamic derivatives, Heat transfer (hypersonic).

21 WMT Wind tunnel Measuring Techniques 110 CAC Computational Acoustics Definition: Conventional measuring techniques mostly rely upon strain gauges and temperature sensors. Non intrusive optical measuring techniques are able to visualise the flow structure and to provide quantitative data relative to both surface characteristics (pressure distribution, transition detection, etc.) and flow field properties (mainly velocity and turbulence). Sub-domains: 1. Pressure: (un)steady pressures, Pitot/multihole probes, PSP (Pressure Sensitive Paints). 2. Temperature and heat flux: Infrared Thermography, thermocouples, hot wire, hot film. 3. Velocity: LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry), DGV (Doppler Global Velocimetry). 4. Flow visualisation: Schlieren technique, shadowgraphy, laser tomoscopy, Rayleigh scattering, interferometry. 5. Surface visualisation: oil film, mini-tufts, infrared or sublimation transition detection. 6. Forces, moments: strain-gage balances (6-component or local loads). 7. Model attitude/deformation: potentiometers, accelerometers, photogrammetry, moiré. Definition: Computational methods for the numerical propagation of sound through internal and external flows. Computational predictions are most often split into noise source modelling and numerical simulation of acoustic propagation. Noise source modelling is strongly problem-dependent (turbulence, blade loads fluctuations, cavity resonances, combustion, vibrations) and is assumed to be covered by domain 302. Methods for the numerical propagation of sound through internal and external flows can be splitted into two categories, (1) integral methods and (2) discretised methods. 1. Integral methods, mostly used for external problems in which acoustic propagation is assumed by the analytical Green's function in free field and uniform flow. The sound is computed at any observer point through a surface or volume integral. 2. Discretized methods assume the discretisation of relevant continuous equations over the propagation medium. Flow non-homogeneities (spatial and temporal) are taken into account from CFD results. Internal and external flows are concerned. Sub-domains: 1. Noise source modelling. 2. Numerical simulation of acoustic propagation.

22 ENP External Noise prediction Definition: Prediction of aircraft noise in view of reducing community annoyance around airports and heliports. This includes jet aeroplanes, propeller aeroplanes, and helicopters. Studies are mainly focussed on transport aviation, but military aircraft and general aviation also are of concern. In each of the following sub-domains, one has to deal with three main activities. - Analytical or numerical simulations. - Tests in static facilities, in wind tunnels, or in flight. - Optimisation of novel designs. Sub-domains: 1. Turbofan or turbojet engines 2. Helicopter turboshaft engines 3. Propeller (high speed and general aviation) 4. Helicopter rotors (main rotor, tail rotor) 5. Airframe-generated noise (high lift devices, landing gears) 6. Installation effects of engines 7. Sonic boom of supersonic aircraft includes ARDEP Sub domain NOIS of ENV domain

23 Taxonomy Area 2: Aerostructures 2 AST AEROSTRUCTURES 201 MMP Metallic Materials & basic processes Definition: High temperature materials for engines and light alloys for airframe. Improvement of the properties of already in use materials, improvement of materials in the process of being introduced, prospection and development of new materials. Development of new assembling technologies and the corresponding modelling. Development of specific tools for materials processing (alloy making furnaces, powder metallurgy, deposition techniques, oxidation and corrosion furnaces, heat treatments furnaces, machining facilities). Techniques of physico-chemical and microstuctural investigations (Xray analysis, scanning electron microscopy and microanalyses). Mechanical characterisation. Sub-domains: 1. Superalloys 2. Aluminium alloys 3. Titanium aluminides 4. New weldable alloys 5. Coatings 6. Oxidation, corrosion 7. Assembling processes 8. Repairing processes 9. Microscopical analyses 10. Chemical analyses 11. Mechanical testing 202 NMP Non-Metallic Materials & basic processes Definition: Organic and ceramic materials in different forms (film, monolith, fibre). Surface protection (oxidation, corrosion, thermal barrier), ceramics for structural and electrical engineering (blades and hot parts of engines, electromagnetic windows, ball bearing, electric insulators, fibres and nanotubes), processing routes (PVD, CVD, sintering, reaction-bonding, directional solidification, cold and hot isostatic pressing, melting and spinning, laser ablation and electric discharge). Sub-domains: 1. Carbide and nitride of silicon 2. Organometallic precursors of ceramics (alkoxides and organosilicon polymers) 3. Organic precursors of carbon (PAN, pitch) 4. Glass and glass-ceramics 5. silica 6. cordierite 7. metallic sulphides and fluorides 8. Polyethylene 9. aramid, glass

24 CMP Composite Materials & basic processes 10. carbon and boron nitride nanotubes 11. thermal barrier coatings 12. Piezoelectric Definition: Life prediction (residual stress, damage propagation, oxidation and corrosion) and multi-scale modelling taking into account the fibre/matrix interface. Development of micromechanical characterisation tools (instrumented microindentation at room and high temperature, push-out and push-in). Ceramic Matrix Composites (CMC) : hot parts for turbine engine (nozzle flaps, thrust vectoring nozzles, flame-holder, exhaust cones), rocket propulsion (thrust chambers, exit nozzles and nozzle throats) and thermal protections. Composites reinforced with long fibres or fillers. Processing routes (sintering, hot pressing, reaction bonding, liquid infiltration, chemical vapour infiltration). Organic Matrix Composites (OMC) : main body and wings for both subsonic or hypersonic aeroplanes and helicopters, outer ducts for engines, tanks, structural components for satellites and rockets, thermal protections. Short or long fibre composites, compounds (premix or nanotubes). Processing routes (press moulding, autoclave, RTM, filament winding, tow placement). Metal matrix composites (MMC) : aero-engines hot parts (compressor disks, drive shafts, blades) and structural components (aircraft landing gear, rocket motor casing, missile fins, satellite antennas). Continuous fibre-reinforced and particulate-reinforced composites. Processing routes (liquid infiltration under moderate pressure, fibre coating and HIPing, powder metallurgy). Sub-domains: 1. CMC: matrices (carbide and nitride of silicon, glass-ceramics, carbon) ; fibres (silicon carbide, carbon, oxide) and fillers (silicon carbide). 2. OMC: matrices (thermosetting resins, thermoplastic polymers, thermostables and elastomers); reinforcement by fibres (carbon, polyethylene, polyaramide, glass, plant fibres) and by particles (mineral, nanotubes). 3. MMC: matrices (conventional titanium alloys, titanium aluminides, nickel-based superalloys, aluminium and magnesium alloys); fibres (silicon carbide, alumina, carbon) and particles (carbides). 4. Elaboration processes. 5. repairing processes.

25 AMP Advanced Manufacturing Processes & Technologies Definition: Advanced Manufacturing Engineering processes involve the design, production engineering and transition to factory operation of competitive manufacturing processes, techniques, methods and tools. Sub-domains: 1. Flexible Manufacturing 2. Robotics 3. composite components 4. fibre-metal laminates 5. Ribbon Organised Wiring 6. High speed machining: metal parts 7. Fabrication simulation: all kind of manufacturing processes to reduce start up time 8. Welding technologies 8.1. Friction stir welding : metal structures 8.2. Laser beam welding: metal structures 9. Explosive forming 10. Advanced castings 11. Super plastic forming: metal structures, in particular titanium 12. Resin transfer moulding: composite structures 13. Tau placement: automated fibre placement, composite structures 14. Thermo-plastics: composite structures 15. Riveted Joint 16. Bonded Joint 17. Conformal antennas 205 SAD Structural Analysis and Design Definition: Structural analysis and design consist in all the steps necessary to guarantee that any structural part will be able to fulfil its requirements. It encompasses the conception and design (with links with CAD) and the prediction/verification of strength to static loads (stress analysis) and low amplitude cycling loads (fatigue). The effects of the environment (such as ageing, thermal loads, moisture effects,...) are included in this domain.

26 AEL Aero-elasticity Sub-domains: 1. Metallic Material constitutive laws (linear elasticity, plasticity, viscolelasticity) 2. Composite laws (linear and non-linear domains) 3. Numerical methods (finite element, solving methods) 4. Composite and multilayer structure modelling 5. Static Stress analysis with damage and failure criteria 6. Fatigue behaviour analysis with crack initiation and propagation 7. Multi-scale modelling methods for CMC, OMC and MMC materials 8. Buckling (linear and non-linear approaches) for metallic components 9. Buckling for composite structures with or without stiffener 10. Post-buckling (crack initiation and delamination propagation) 11. Assembling modelling (rivets, bonding, FSW techniques,..) 12. Optimisation methods Definition: Study of flexible structures situated in a flowing fluid. The origins are in the field of aerospace engineering (aeroplanes, helicopters rotors, turbomachineries, launchers and missiles), but aeroelasticity concerns also civil engineering (bridges, towers), mechanical and nuclear engineering. The first objective of aeroelasticity is to guarantee the integrity of the structure in the flow. Aeroelasticity is the study of the mechanics of coupled aerodynamics-structure systems: the structure is taken in the usual mechanical sense of the term, which is to say that it includes the passive structure and the structured coupled to control systems (flight controls, control law). In fact, the term aero-servo-elasticity is often used. High temperature environments can be important in aeroelastic problems, hence the terms aerothermo-elasticity. So aeroelasticity incorporates the theory of continuum mechanics, fluid mechanics, and automatic systems. The scientific fields concerned, then, are steady and unsteady aerodynamics, the static and dynamic structure with its linear or non-linear properties, the servo controls, also with their linear and non-linear properties, and the coupling loop between the aerodynamics, the structure, and the systems. Aeroelastics problems can be static and dynamic: In dynamic aeroelasticity, there is a further subdivision of problems into two broad types. The first type is when the flow is unsteady and the structure is in a steady position, but behaves dynamically. This is the case of problems having to do with atmospheric turbulence, boundary layer separation, and shock wave-boundary layer interaction. Buffeting also enters into this category of problems. The second type of general aeroelasticity problem has to do with those aeroelastic instabilities where the motion of the structure causes the forces, in that the aerodynamic forces do not exist without this motion. Flutter falls into this category and is the most important topic of aeroelasticity.

27 BVA Buckling, Vibrations and Acoustics Sub-domains: 1. Static aeroelasticity: Linear and non linear structure, Steady aerodynamic, Static deformation, Static divergence, Aeroelastic optimisation. 2. Dynamic aeroelasticity: Structural dynamic (linear and non linear), Unsteady aerodynamic (linear and non linear), Fluid structure coupling, Fluid structure systems coupling, Flutter, Forced response. 3. Numerical aeroelasticity: Unsteady aerodynamic, Stability and response prediction, Aeroelastic optimisation, (multidisciplinary optimisation), Aeroelastic model updating, Aero-servo-elasticity. 4. Experimental aeroelasticity: Unsteady aerodynamic, Flutter model (design, manufacture, ground testing, wind tunnel testing). 5. Aeroelastic Certification: Ground vibration test, Flutter flight test. Definition: Activity on buckling consists of the development, improvement and validation of experimental and numerical methods for the prediction of buckling phenomenon and optimisation of structural components (metallic and composite materials) in aerospace domain. Vibrations and Vibro-Acoustics: Objectives of the structural dynamic are to determine the dynamic behaviour of structural systems excited by external or internal forces (mechanical, aerodynamics or acoustic) in order to guarantee the integrity of the structure in the environment and the comfort of the users. The objectives of the vibro-acoustics are the same for a structure coupled with a fluid. Two types of problems can be consider. The first type concerns the internal noise generated by vibrating structures. The second type concerns the acoustic discretion where the external noise is generated by vibrating structure. The studies concern the physical understanding of the mechanic and acoustic phenomena s, their description, their quantification with theoretical, numerical and experimental means.

28 SMS Smart Materials and Structures Sub-domains: 1 - Structural dynamics: 1.1. Structural dynamic modelling: Material modelling (viscoelastic media, composites, multilayer structure); Numerical method( (Analytical, Finite Element analysis), Statistic Energy Analysis); Linear and non linear analysis; Damping modelling; Structure internal fluid interaction (sloshing) Multibody dynamics modelling: Kinematics and dynamics of rigid and flexible components 1.3. Stress Waves in Solids: Waves propagation 1.4. Structural Model updating 1.5. Dynamic Structural optimisation 1.6. Shocks and vibrations: Transient response, Low frequency range, Medium and high frequency ranges 1.8. Random Vibrations in Structural Mechanics: Linear and non-linear systems, Random excitation (turbulence, noise, acoustic) 1.9. Experimental Methods in Vibrations: Vibration properties of materials, Vibration technique in nondestructive testing, Systems excitations, transducers, Data acquisition, Signal processing and analysis, 1.8- Experimental Modal Analysis, FRF measurements 2 - Elasto-acoustic: 2.1. Material properties: Homogeneous material, composites, viscoelastic media, multilayer, etc.; Acoustic material 2.2. Modelling: Analytical approaches, Finite element analysis, Boundary Element analysis, Statistic Energy Analysis 2.3. Sound Structure Interaction: Acoustic propagation, Acoustic radiation, Acoustic transmission through structures, Acoustic reflection from elastics structures, Acoustic excitation, Acoustic fatigue, Structure and fluid damping 2.4. Experimental Identification Definition: This domain consists in to equip structures with sensors, actuators and intelligence in order to give them some autonomy, adaptation capabilities or reduce the operational costs or nuisances (noise...). The sensors provide the knowledge of the internal state and of the external environment. The actuators give the ability to adapt to internal and external changes. The intelligence permits the autonomous capacity to decide the optimal way of adaptation.

29 SMT Structures behaviour and Material Testing Sub-domains: 1. Miniaturisation of sensors (piezoelectric devices, optical fibers,..) 2. Integration of sensors 3. Active Piezoelectric materials 4. Electrostrictive materials 5. Single crystals 6. Magnetostrictive materials 7. Electrorheological 8. Shape memory alloys 9. Actuators 10. Micro-motors 11. Control strategies 12. Multi-functional materials 13. Health Monitoring System 14. Control of vibration 15. Shape Control 16. Active flow Control 17. UAV, mini UAV Definition: Development and use of test facilities in order to get inputs for prediction tools (material properties characterisation of metallic and composite materials), validate prediction tools (determination of local or/global information such as strain, stress, plasticity, cracks, delamination phenomenon,..) and to verify the behaviour of sub-components or real structure (limit strength, fatigue behaviour,..). Sub-domains: 1. Constitutive laws (metallic and composite materials) 2. Experimental static component behaviour 3. Non-linear characterisation with and without temperature environment 4. Buckling testing 5. Diffusitivity measurements (thermal properties. NDT) 6. Electrical and electromagnetic properties measurements (NDT) 7. Optical properties (NDT) 8. X Ray radiography (NDI) 9. Ultrasounds with and without contact (Air coupled or laser) 10. Eddy Current (NDI) 11. Thermography method (NDI) 12. Optical techniques (holography, shearography, Moire)

30 INP Internal Noise prediction 211 HAA Helicopter Aero-acoustics Definition: Activity on internal noise prediction consists of the development, improvement and validation of experimental and numerical methods for the prediction and the reduction of internal noise (aeroplane, helicopter, launcher). This activity is a part of the Vibration and Vibroacoustic domain. To solve an Internal Noise Problem, we need the knowledge of the excitation sources, the dynamic behaviour of the structure, the propagation way of the vibration in the structure and in the internal fluid. Sub-domains: 1. Material properties: Homogeneous material, heterogeneous structure, Composite material, viscoelastic media, multilayer, etc., Acoustic material, porous material, Material optimisation. 2. Modelling: Analytical approaches, Finite element analysis, Boundary Element Analysis, Statistic Energy Analysis, Energy diffusion; 3. Excitation sources: mechanic, aerodynamic, acoustic; Acoustic propagation, Acoustic radiation, Acoustic transmission through structures, Acoustic reflection from elastics structures. 4. Experimental Identification. Definition: Helicopter aeroacoustics consists in: - studying and identifying the aerodynamic phenomena causing noise generation and influencing noise radiation. The occurrence of these phenomena and their relative contributions to noise, strongly depend on flight conditions (take-off, descent, level flight at low, medium and high speed) and on the type of helicopter. - developing and validating computational tools for prediction of helicopter noise with the following objectives: - quantification of helicopter nuisance, - quiet helicopter design (rotor, turboshaft air intake and acoustic lining), - determination of low noise flight procedures (for civil applications) - determination of low detectability manoeuvres and flight procedures (for military purposes). Helicopter noise sources comprise main and tail rotors and turboshaft engines. Research activities consist in: - physical modelling and numerical simulations, - wind tunnel or static tests and helicopter flight tests. Key issues for an accurate numerical prediction of helicopter noise are: - for rotor noise, a precise prediction of the main rotor wake and vortices which may interact with main rotor and even tail rotor blades, depending on flight conditions. - for turboshaft engine noise, a precise prediction of acoustic propagation in the complex flow and geometry of the engine air intake.

31 NOI Noise Reduction Sub-domains: 1. Sub-domains according to the origin of the sources: 1.1. main rotor noise 1.2. tail rotor noise 1.3. turboshaft engine noise 2. Sub-domains according to the nature of noise: 2.1. discrete frequency noise related to periodic aerodynamic phenomena The nuisance from helicopter rotors is very much increased when a certain type of discrete frequency noise called "helicopter rotor impulsive noise" occurs. This "impulsive noise" includes Blade Vortex Interaction (BVI) noise in descent and low-to-medium level flight and High Speed Impulsive noise (HSI) broadband noise, mainly due to interactions between rotating components (rotor and compressor blades) with incoming turbulence. Definition: 1. Internal noise reduction Active Control. The aim is to decrease the level of noise due to the vibrations of structures with the use of active control algorithms able to take into account different noise sources, i.e. wide band excitations. 2. External noise reduction Reduction at the source; acoustic absorbing materials (passive and adaptive). Link with ATM and Human Factors (noise perception) Sub-domains: 1. Active Control algorithms 2. Techniques in relation with actuators and sensors such as piezoelectric or piezoceramic materials, electrostrictive ceramics and their mechanical modellisation. 3. Automatics and real time systems for the study and for the realisation of controllers 4. Optimisation of the location of patches on the structures 5. Modal identification of structures 6. Knowledge of noise sources and identification of acoustic leaks 7. Acoustic measurements for the validation of Active Control 8. Sources: 8.1. Optimisation of aerodynamic and acoustic performance through new design of fan blade and vanes, advanced propellers (possibly uneven spaced), and helicopter rotors Novel aircraft designs to mask some sources, or to alleviate installation effects (interactions) on noise generation. 9. Acoustic linings: 9.1. New concepts of passive or adaptive materials 9.2. Extensions to high temperatures on the exhaust duct 10. Noise abatement procedures