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Agency: European Commission | Branch: FP7 | Program: CSA-SA | Phase: AAT.2013.7-7. | Award Amount: 534.35K | Year: 2013

As mentioned in the Executive Summary of the Strategic Research & Innovation Agenda, Aviation has an important role to play in reducing greenhouse gas emissions as well as noise and local air quality issues. The continuous increase of air passenger transport generates an increasing use of hydrocarbon fuel with excessive emission of CO2 and NOX (greenhouse gases, pollutants and noise). It is well known that commercial aircraft operations impact the atmosphere by the emissions of greenhouse gases and greenhouse gas precursors, and also through the formation of contrails and cirrus clouds. In 2011, during the Aerodays in Madrid, the EC launched the future of Aeronautics in the ACARE Flight Path 2050 Vision for the Aircraft report containing the ambitious goals on the environmental impact with 90% reduction in NOx emissions, 75% reduction in CO2 emissions per passenger kilometer, and the reduction of the noise in by 65%, all relative to year 2000. To achieve the ACARE Strategic Research & Innovation Agenda green aeronautics technologies will play a more and more dominant role in mastering the challenge on Protecting the environment and the energy supply. GRAIN2 Supported Action, based on the same collaborative and win-win spirit introduced in former EU-China GRAIN project, will provide inputs and roadmaps for the development of large scale simulation strategies for greener technologies to meet the above future requirements on emissions, fuel consumption and noise. To reach these targets, green technologies efforts will have to be collected and prospected in three major lines: Air vehicle, Air Transport System and Sustainable Energies. Three folds to be investigated as future greening technologies: 1) Greening the aircraft and the aero engine 2) Greening the operational environment 3) Reducing the carbon foot print of aviation via sustainable alternative fuels

Agency: European Commission | Branch: H2020 | Program: RIA | Phase: MG-1.10-2015 | Award Amount: 1.80M | Year: 2016

The proposed project, IMAGE, is relevant to Topic MG-1.10-2015, aiming to enhance the EU-China collaborative effort focusing on Innovative methods and numerical technologies for airframe and engine noise reduction. The project consortium consists of 12 partners. The purpose of IMAGE is to investigate experimentally and numerically innovative airframe and engine noise-reduction technologies and, in a systematic conjunction, to develop robust methodologies of addressing these technologies. Airframe noise is addressed by tackling landing gears and high-lift devices, and engine noise through its fan component. Fundamental investigations of three key control strategies are carried out: plasma actuation, turbulence screens and innovative porous materials, on a platform of three configurations, relevant to airframe and aero-engine noise generation and control, including a wing mock-up, tandem cylinder and engine-fan duct. Beyond this, IMAGE explores further the installation effect of aeroacoustic engine-jet/wing interaction with a simplified configuration, as well as low-noise concepts and optimal noise-actuation methods by means of aeroacoustic optimization. The project will conclude a comprehensive understanding of the physical mechanisms concerning flow-induced airframe and engine-fan noise generation, propagation and control, and of further improvement of beam-forming technology and noise source identification in aero-acoustic experimental analysis. The experiment will generate well-documented database, supporting the development of numerical modelling and simulation methodologies for reliable validation and verification. To this end, with technical synthesis and industrial assessment, the noise control methods will be optimized and be facilitated towards potential industrial use, and the methodologies developed should form a robust part of advanced tools in industrial practice.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: AAT.2013.4-2.;AAT.2013.1-1. | Award Amount: 1.31M | Year: 2013

The aeronautical industry lacks confidence in the accuracy of computational fluid dynamics (CFD) in areas of highly non-linear, unsteady flows close to the flight envelope borders, which demands advanced approaches and methods. The family of Hybrid RANS-LES Methods (HRLM) is the best candidate for the next generation of CFD methods for increased fidelity at industrially-feasible expense. While HRLM have been proven to perform considerably better than conventional (U)RANS approaches in situations with strong or massive flow separation, they are hampered by the Grey Area issue once they have to deal with thin separation regions and where shear layer instabilities are weaker. As exactly these areas are of high importance for aircraft performance (lift, loads) the acceptance of HRLM strongly depends on the ability to mitigate the extent of the Grey Area (GA). With the new/advanced Grey Area mitigation approaches, the Go4Hybrid project offers hybrid RANS-LES methods that improve predictive capability with increased flexibility and reduced user decision load. Hence, the incentive for future use of these highly sophisticated methods goes in line with a considerably high impact: Progress beyond the state-of-the-art for non-zonal methods is achieved by the development and demonstration of generally-applicable extensions to mitigate the Grey Area problem, thereby extending their applicability to important industrial flows at the performance frontiers. For embedded methods, a focus will be placed on improving methods so that they are applicable to arbitrary complex geometries, as opposed to many existing techniques that require e.g. canonical boundary layer assumptions or homogeneous flow directions and are hence fundamentally less flexible. In general, development work will pursue a number of key goals contributing to extended applicability, improved accuracy, increased flexibility, reduced user decision load and increased Technology Readiness Level of hybrid approaches.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: AAT.2012.1.1-1. | Award Amount: 7.67M | Year: 2012

The central goal of JERONIMO is the understanding of the physical mechanisms of ultrahigh bypass ratio (UHBR) engines with a bypass ratio (BPR) larger than 12 and the related installed jet noise with potential jet-wing interaction. The aim is to reduce uncertainties in jet noise characterisation of this novel installation configuration by wind tunnel tests and predictions and being able to derive design recommendation for future UHBR Engine jet noise reduction. For the achievement of those goals, UHBR engines have to be investigated experimentally for their jet noise characteristics in the isolated and installed configuration. A consistent database will be built at European level in the major jet noise test facilities, at NTF and CEPRA19, applying advanced and improved measurement techniques such as far-field noise & near-field pressure measurements, combined with aerodynamic methods like PIV. In parallel, existing CFD-CAA simulation tools will be adapted and validated (or used state-of-the-art only), and the overall methodology to predict flight stream effects and complex interaction mechanisms for UHBR engine jet noise at medium and full scale will be developed. This will need an identification of the key physical or key flow features by a detailed processing of the experiments together with numerical data for steady and unsteady flow conditions and acoustics in combination with analytical/theoretical methods, such as flow instability analysis. Innovative nozzles will be designed regarding the UHBR architecture, tested and assessed to reduce UHBR engine installed jet noise. Finally, recommendations in term of e.g. the relative position of nozzle/wing will be provided, the methods & data will be assessed. An evaluation for aircraft noise and a common database will be established.

Wang L.,TU Berlin | Mockett C.,TU Berlin | Knacke T.,TU Berlin | Thiele F.,CFD Software Entwicklungs und Forschungsgesellschaft MbH
Notes on Numerical Fluid Mechanics and Multidisciplinary Design | Year: 2012

Detached-Eddy Simulation (DES) is a promising method for efficient simulation of broadband noise at minimal computational cost. Here, results from a study of broadband noise simulation using state-of-the-art DES methods are presented for a rudimentary landing gear configuration. The DDES and IDDES variants are compared with experiments in incompressible simulations. IDDES shows mild improvement in agreement and some increase in the resolution of high frequencies. An attempt is made to independently verify published results for far-field sound prediction, using a compressible simulation coupled with Ffowcs-Williams/Hawkings (FWH) integration. In contrast to the published results, our results do not provide evidence of unexpectedly strong roles played by the ceiling or by quadrupoles. Our results furthermore predict much lower far-field noise levels than the published results. Good agreement between solid and permeable FWH surfaces is found as long as the permeable surfaces are open downstream. © 2012 Springer-Verlag Berlin Heidelberg.

Mockett C.,CFD Software Entwicklungs und Forschungsgesellschaft mbH | Mockett C.,TU Berlin | Fuchs M.,TU Berlin | Thiele F.,CFD Software Entwicklungs und Forschungsgesellschaft mbH
Computers and Fluids | Year: 2012

Detached-Eddy Simulation (DES) was originally conceived for applications such as external aerodynamic flows with thin attached boundary layers and large-scale flow separation. In recent years a key modification to DES, known as IDDES, has been proposed that aims to extend its capabilities to include wall-modelled LES, which is particularly beneficial for cases typified by internal flows featuring thick boundary layers. IDDES of planar channel flow and the separating and re-attaching flow over periodic, two-dimensional hills is reported.Channel flow results indicate a satisfactory validation of the method, with a mild deviation believed to reflect an inherent numerics-sensitivity of IDDES. Very good agreement with benchmark data is achieved for the periodic 2D hills. In a systematic parameter study, the effects of turbulence modelling variation as well as strong grid and time step coarsening are investigated and discussed. The response of the method can generally be described as robust. The limits of time step coarsening are seen most clearly in the relationship between bulk flow and the driving pressure gradient. The importance of reporting this information is hence highlighted.A further investigation concerns the combination of IDDES with an all-y + RANS wall treatment. For both test cases, grids without wall-normal refinement are employed as a particularly challenging test. In the planar channel, the Reynolds number dependence of grid resolution has been shown to be successfully eliminated. The results for the periodic hills are less satisfactory, which is attributed to the poor resolution of the hill-crest and early shear layer. A significant improvement over simulations without the all-y + treatment however demonstrates the enhanced robustness achieved. © 2012 Elsevier Ltd.

Agency: European Commission | Branch: FP7 | Program: JTI-CS | Phase: JTI-CS-2010-4-GRC-02-006 | Award Amount: 147.28K | Year: 2011

Reduction of aerodynamic drag is central to the ACARE 2020 goal of reducing fuel consumption in air transportation. For rotorcraft, the majority of the drag occurs due to extensive flow separation around the fuselage and rotor hub. Such highly unsteady flows present significant challenges for computational fluid dynamics (CFD) techniques in terms of solution fidelity and computational expense. However, a new family of hybrid RANS/LES techniques addresses this conflict by mixing pure modelling (RANS) and partial resolution (LES) of the turbulent motion to provide an optimal tradeoff between solution fidelity and computational cost. Of these, the well-established detached-eddy simulation (DES) method has been selected for the HELIDES simulations due to its high maturity and inherent suitability. Through participation in numerous EU projects (e.g. FLOMANIA, DESider, ATAAC), the consortium has developed a very high level of expertise with the development and application of these methods, including to helicopter fuselage simulation. The HELIDES consortium has furthermore played a central role in the implementation and validation of cutting-edge DES methods in an efficient, incompressible, unstructured CFD solver that can capture complex geometries with rotating components. Furthermore, novel analysis techniques for the quantification of the random error in statistical quantities provides a pragmatic means to manage the significant problem of finite simulated time samples. With these well-suited tools and expertise, together with access to very large computing resources, the HELIDES consortium considers itself ideally equipped to perform the demanding high-fidelity simulations specified by the Call.

Michel U.,CFD Software Entwicklungs und Forschungsgesellschaft mbH
21st AIAA/CEAS Aeroacoustics Conference | Year: 2015

The flight effect on jet mixing noise cannot be determined correctly in open jet wind tunnels by using the industry standard correction method for the shear layer influence. One important consequence is that the forward arc amplification of jet noise observed in many flyover tests cannot be replicated in free-jet windtunnel tests. The reason proposed in this paper is a coherence loss in the radiated sound field due to scattering in the tunnel shear layer. This effect is unimportant for point sources but becomes important for distributed and partly coherent sources like jet noise. The effect is proportional to the tunnel Mach number, to the ratio between thickness of the tunnel shear layer and the jet diameter, and to the ratio between the propagation distance outside the shear layer to the wave-normal distance of the microphone. As a consequence of the loss of coherence the sound-pressure levels measured outside the tunnel are too low and the resulting relative velocity exponents too large. The effect depends on the geometric conditions which differ between the various tunnels. © 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All Rights Reserved.

Michel U.,CFD Software Entwicklungs und Forschungsgesellschaft mbH
22nd AIAA/CEAS Aeroacoustics Conference, 2016 | Year: 2016

The flight effect on jet mixing noise can be predicted with a precision of a few decibels with scaling relations that are derived solely based on the Lighthill equation using relatively simple equations and without any arbitrary constant. The prediction formulas are based on measurements of jet mixing noise of static jets with the same nozzles and identical flow temperatures. The flight-effects theory of Michalke and Michel for jet noise is revisited. Scaling relations are derived based on the convective Lighthill equation and assuming that jet noise is caused by instability waves in the jet’s shear layer. The flight velocity yields a Doppler amplification into the forward arc while the interference within the non-compact and wavelike jet-noise sources results in a rear arc amplification best known for static jets. An important influence on the radiation of jet noise is the stretching of the flow field of the jet under the influence of the flight stream, which increases the source volume, the coherence length scales of the sources in the mean flow direction and the frequencies in flight. The influence of the interference in the azimuthal direction of the source region must also be considered. A comparison is made with the experimental Aérotrain “flyover” data and the results show an agreement within ±1 dB of the OASPL for a large range of emission angles for which shock-free static data are available. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Agency: European Commission | Branch: H2020 | Program: CS2-RIA | Phase: JTI-CS2-2015-CFP02-ENG-03-02 | Award Amount: 398.00K | Year: 2016

The project, entitled Industrialisation of Jet Noise Prediction Methods (INSPiRE), addresses fully the scope outlined in Topic JTI-CS2-2015-CFP02-ENG-03-02 Jet Noise Reduction Using Predictive Methods. Turbulence-resolving CFD coupled to efficient far-field integration methods is established as an accurate means for the prediction of isolated jet noise. The trend towards increasing fan diameters however leads to the growing importance of installation effects, such as jet-flap interaction noise. The simulation of such effects however requires numerous developments in the underlying numerical approaches to achieve increased computational efficiency, flexibility and reduced user burden. Such improvements will be developed, implemented and validated for complex installed jet flows (including configurations with noise-reducing design features) within the INSPiRE project. Together with comprehensive best practice guidelines, the developments will make a significant contribution to improving confidence in simulation methods and to achieving industrial exploitation of turbulence-resolving approaches. This is furthermore ensured by the implementation and validation of methods directly in the HYDRA software. High cost-efficiency and low technical risk of the INSPiRE project is facilitated by the input of advanced methods and best practice developed within the framework of previous and ongoing projects, both European and nationally-funded. A strong and positive impact is foreseen, both towards the challenging noise reduction goals set in the renewed ACARE SRIA, as well as towards the Horizon 2020 pillar of building industrial leadership in Europe. Clear perspectives for the exploitation of INSPiRE results, both by the European aero engine OEM sector and by the SME coordinator, are identified.

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