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JEt noise of high bypass RatiO eNgine: Installation, advanced Modelling and mitigatiOn

Periodic Report Summary 2 - JERONIMO (JEt noise of high bypass RatiO eNgine: Installation, advanced Modelling and mitigatiOn)

Project Context and Objectives:
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 farfield noise & near-field sound pressure easurements, combined with aerodynamic methods like PIV. In parallel, existing CFD-CAA simulation tools will be adapted and validated, 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.

From this context these are the main objectives, followed by JERONIMO:
* to understand the physical mechanisms of UHBR Engine (BPR>12) installed jet noise with jet-wing interaction
* to develop and validate engine jet noise characterisation and prediction processes based on anechoic wind-tunnel tests and numerical simulation
* to acquire the ability and the means to derive low-noise design guideline for future UHBR engine/aircraft products.

Project Results:
This section describes the activities and achievements from the technical work packages during M01-M18.

There have been major activities in work package WP1 “UHBR Jet Noise Characterization“.

First, the aerodynamic parameters of the UHBR nozzle have been agreed and the aerolines of the exhaust system has been designed. The instrumentation requirements have been defined, the mechanical design of the exhaust system for the large-scale WTT is completed and its manufacturing is progressing well.

The test requirements for the first large-scale WTT in the Noise Test Facility of QinetiQ have been defined and agreed with all partners working in WP1 to WP4. The test preparation is progressing well.

Beside this, the approach for the study of the effect of the external boundary layer and the numerical methods are defined. The requirements are fed into the nozzle instrumentation and test definition.

Finally, the development of the advanced measurement techniques are progressing according to the work plan. The Critical Technology Review ahead of the first large-scale WTT at QinetiQ’s NTF have been conducted and three criteria i) benefit to the project, ii) readiness level and iii) costs for each technology assessed.

During the reporting period the main objectives for WP2 “Parametric Studies of Jet Installation Noise“ were to pursue the first activities at small scale, to prepare the first campaign of “installed nozzle” tests at large scale in wind tunnel, and to kick off activities on numerical simulation for jet aeroacoustics.
Concerning the activities at small scale: partners started preparing experimental work and progressed on numerical work and modelling. This allowed numerical activities to progress early in the project.
Concerning the activities at large scale: AIF designed various nozzle installations under its wing model. The main industrial project partners AIF, RRD and SN discussed and proposed to all partners of the Consortium relevant parameters to study for the jet installation noise. The set of “installed models geometries” and aerodynamic conditions constitute the backbone of the installed part of the “test matrix specifications” for the wind-tunnel test campaigns in the project. The requirements of the partners for the first large-scale test campaign were issued. The set of installed cases geometries were frozen.
Numerical simulation activities aiming at reproducing large-scale tunnel test cases were kicked off, with a focus on meshing.

Regarding “Specifications & Technology Evaluation”, which are covered by WP4 the main objectives during the reporting period were to provide specifications for common baseline nozzle, wind-tunnel test (WTT) campaigns and numerical simulations.
Concerning the definition of common baseline nozzle specifications, WP4 partners have worked jointly to define a list of the most relevant parameters to fit with future UHBR application on aircraft. With this work, flight conditions, global data and main geometrical nozzle parameters have been defined as well as jet operating conditions.
The second achievement concerns test matrix specifications. In particular, nozzle operating conditions, aerodynamic and acoustic test phases have been defined with the aim of studying a broad spectrum of physical effects for both isolated and installed configurations.
Furthermore, common baseline test cases have been specified to numerical partners in order to gather comparable numerical results for the assessment of methods developed within JERONIMO.

Finally, a jet noise database format has been defined to harmonize the exchange of aerodynamic and acoustic data which will be obtained by WTT measurements and numerical simulations.

The following section describes the main activities and achievements from the technical work packages during M19-M36.

In WP1 “UHBR Jet Noise Characterization“ the manufacturing of the UHBR JERONIMO nozzle and nozzle instrumentation is completed. The preparation of the large-scale wind tunnel tests are progressing well.

The computational study on the effect of boundary layer size on the far-field noise by the partners is progressing well.

The development of the advanced measurement techniques are progressing according to the work plan. The techniques have been demonstrated and applied in small-scale test. The processing techniques are providing valuable data for the understanding of source mechanism of jet-flap interaction noise. The techniques are getting optimized for their application in large-scale tests.

During the reporting period the main objectives for WP2 “Parametric Studies of Jet Installation Noise“ have been
* to finalise activities at small scale and summarize knowledge in a workshop
* to prepare both the first and the second campaigns of “installed nozzle” tests at large scale in wind tunnel
* to continue activities on numerical simulation for jet aeroacoustics.
Concerning the activities at small scale, modeling and simulation strategies were defined and implemented. Experimental databases and modeling results were delivered.
Concerning the experimental activities at large scale, test preparation activities were performed jointly with WP1 and WP3. Test requirements were issued to the test suppliers. Design and manufacturing of models and instrumentation were performed.
Numerical simulation activities aiming at reproducing large-scale tunnel test cases progressed. First results were generated on the isolated nozzle baseline case. Strategies on the meshing of the wing model and on the computational acoustic processing were defined and started to be implemented. Source analysis was kicked off.

The main objectives of WP3 “Innovative Low Noise Nozzle for UHBR“ are to design, manufacture and test several innovative nozzles: A serrated nozzle and two advanced low noise nozzles. The validation of these nozzles include an experimental characterization in an aeroacoustic wind tunnel and numerical investigations using high-fidelity simulation tools that reproduce the wind tunnel test (WTT) configurations. Both experimental and numerical studies are to be performed with installation effects in order to investigate jet-wing interaction noise. Furthermore, experiments will also be carried out using the baseline nozzle for read across purposes with the WP1 tests. Finally, the outcomes of the WP3 are to be used by the Technology Evaluation in WP4.

During the reporting period, test preparation and numerical assessment activities have been pursued. Specifications of the serrated nozzle and of an adapter for the nozzle installation on the rig support have been defined and the design process has been engaged for both. Partners of WP3 have further discussed and drafted an updated version of the test matrix and of the acoustic and aerodynamic metrology requirements. Furthermore, the implementation of the meshing methodology for the high-fidelity simulations has been kicked-off and preliminary computations of a lobed nozzle geometry have been performed.

During the reporting period WP4 “Specifications & Technology Evaluation” has been focused on task T4.2/Database creation and dissemination.
Here, the main objectives were to
* provide to the numerical partners the specifications for the post processing of the acoustic and aerodynamic data with the aim of allowing a proper cross comparison between numerical and Wind Tunnel test
(WTT) results.
* provide an overall definition of a common database format for all the collected WTT and numerical data.
Concerning the acoustic output specifications for numerical partners, AIF has defined different azimuthal arcs of far-field microphones for three radial distances from the model nozzle exit in order to study polar/azimuthal directivities.
Beyond acoustic specifications, aerodynamic output requirements have been also defined with the objective of fully characterize jet aerodynamics and to allow a proper comparisons and understanding of acoustic data.
Finally, T4.2 activities during the reporting period has concerned the identification of the type of data which will be generated during JERONIMO project as well as the specifications of the output format for each kind of results file.

Potential Impact:
JERONIMO is mainly addressing airframe and engine related installation noise effects in the topic AAT.2012.1.1-1.Flight physics, aiming at reduced noise. Major objectives are the reduction of noise generation and thus perceived noise new engine architectures of UHBR installation. The benefits from JERONIMO will come into effect through the prediction and understanding of this novel configuration, and a comprehensive evaluation of low noise installed concepts. The potential of these concepts will be numerically and/or experimentally assessed concerning the reduction of noise sources generated by jet wing interactions. Exploring and assessing of concepts is one purpose what the JERONIMO project aims at. Therefore it is necessary not only to perform experimental and numerical analysis but also to provide clear guidance and recommendations on these concepts for an industrial realization. As a result, JERONIMO will have a direct impact on the development of new concepts and technologies towards an efficient and low-noise system integration by improving the understanding of prediction of UHBR engine integration.

JERONIMO is oriented towards the long-term objective of the industrial development of European green aircraft, which might enter into service between 2020 and 2030. This kind of aircraft would directly benefit from all the advantages offered by engines in terms of specific high efficiency, low fuel consumption and reduced pollutant emission as well as reduced noise radiation.

The technical and economic success for such an aircraft to effectively address the ACARE challenges of air transport efficiency and reduced environmental pollution. Community noise is expected to be significantly impacted by jet installation noise and JERONIMO will verify this point. Additionally the recently developed FLIGHT PATH 2050 requires additional noise reductions to an overall level of 65% below the values in 2000. JERONIMO takes action on this aeroacoustic issue by providing the ability and means for the European industry to design for low noise the future commercial airliners. Additionally JERONIMO also provides early rules for installed noise mitigation and evaluates the robustness of these rules on novel concepts.

JERONIMO will considerably contribute to the enhancement of the scientific, technical and technological abilities for future programmes, that European aerospace industries – airframers as well as engine manufacturers - will need to realize new green aircraft. JERONIMO will provide an additional impact on Aeronautics and Air Transport, Greening the Air Transport, and also improving the Cost Efficiency and Pioneering the Air Transport of the Future.

JERONIMO will provide key support for furthering our fundamental understanding of installation noise. We now need the combination of scientists and industry engineers to provide conclusive answers with respect to source mechanisms and how they may influence engine / aircraft design. Recent EU-funded programmes have delivered substantial progress in numerical simulation methodologies such that it is now clear that a concerted collaborative effort between experimentalists, theoreticians and numerical modelers will deliver new knowledge on installation noise mechanisms.

Significant competitive advantage will result from the ability to industrialize concepts and technologies that will be applicable to all conventional airframe/engine architectures. Advanced low-noise technology usually first finds application in large turbofan engines for the long-haul sector of the aircraft market. The short/medium haul sector has traditionally lagged by a minimum of 10 years in the incorporation of the latest technologies into new products. Furthermore, the best and most recent European products may need a retrofit in the course of their production life to address strong competitive challenges and tougher noise requirements from local airports; this possible retrofit is driven by the long production cycles in the aeronautic industry.

JERONIMO will provide technologies applicable to all these markets. JERONIMO will have a significant impact in reinforcing the competitiveness of European engine and airframe manufacturers. The project has the ambitious objective of bringing innovative concepts to higher technology readiness levels. This effort will be central to the Generation 2 technology ‘breakthrough’ in the field of aircraft engine jet noise control. The global aerospace market is fiercely competitive. US research has been aggressively investigating innovative noise control concepts, particularly in the field of jet noise and power plant integration acoustics. Specific noise programmes such as QAT (Quiet Aircraft Technology) are taking advantage of dedicated funding from the US government that mobilizes all the resources available in the US to provide the breadth and depth of experience necessary. In order to compete in a market highly conditioned by environmental performance, it is crucial for Europe to back a similar effort. JERONIMO will improve European competitiveness by combining the best European expertise. Finally, by further reducing noise and identifying innovative noise reduction solutions, JERONIMO will make also a significant contribution towards the major social objectives of the European Community. Notable aspects include:

A) Employment – JERONIMO will lead to quieter aircraft and reduced product development times and costs, allowing the European aeronautical industry to maintain a strong position, enabling it to win market shares and therefore preserve and develop employment in Europe. Currently the European aircraft industry employs 430,000 directly among which 19% on engines, and a further 800,000 indirectly through its supply chain, which includes a significant number of SMEs. On the contrary, the American aircraft industry employs 610,000 directly. Predicted growth in aircraft traffic is expected to be 5% per annum with 12,800 new aircraft to be produced before 2013 representing a potential market of $800 Billion. The European engine industry has a long-term goal not to just retain existing market share but to increase it from the current level of 30% in the next 10 years. The state-of-the art technologies and improvements in noise levels, lead times and development costs that
will result from this proposal are essential to achieve these goals.

B) Transport – JERONIMO aims to provide the technology to reduce aircraft noise to allow aviation growth in harmony with other types of transportation and thereby to enable air travel to become a mass transportation medium for both people and goods. Sustainable economic growth boosted by the liberalization of commercial exchanges and lower cost transportation of goods will provide a long-term benefit for all citizens.

C) Quality of life and Health – By helping to reduce aircraft noise JERONIMO will contribute to reduce the noise exposure to communities around airports. This will have an impact on approach certification noise levels, and therefore for communities living very close to the airports (within 4 miles). Reducing installation noise will trim down the noise footprint surfaces around airports and increase the comfort of the people affected by air transport acoustic annoyance. Furthermore, by helping the development of quieter air transport, JERONIMO will have a contribution to a reduction in health costs.

List of Websites:
www.fp7-jeronimo.eu