Community Research and Development Information Service - CORDIS

  • European Commission
  • CORDIS
  • Projects and Results
  • Final Report Summary - EASIER (Experimental Acoustic Subsonic wind tunnel Investigation of the advanced geared turbofan Regional aircraft integrating HLD innovative low-noise design)
FP7

EASIER Report Summary

Project ID: 632462
Funded under: FP7-JTI
Country: Germany

Final Report Summary - EASIER (Experimental Acoustic Subsonic wind tunnel Investigation of the advanced geared turbofan Regional aircraft integrating HLD innovative low-noise design)

Executive Summary:
In EASIER noise-characterisation of low-noise technologies developed within the frame of the GRA-ITD in Cleansky 1 was performed. In order to do this a Wind-Tunnel model, which was developed in the frame of the Cleansky-project ESICAPIA, was used. Within EASIER the partners University of Rome 3, REVOIND Industriale and IBK were implemented. REVOIND Industriale was later replaced by EUROTECH.
In order to perform the test-activities specific requirements for the tests and the WT-model needed to be defined. Due to the fact that the model is large (span of 4.9m) all activities needed to be planned with care including logistics onsite in the WT. The WT was chosen to be the RUAG Large-Wind Tunnel in Emmen.
In order to optimize and de-risk activities the design and manufacturing of the ESICAPIA model was done in strong link with the EASIER project thus taking into account acoustic requirements, like
- Different configuration in the WT (dorsal vs. ventral), model needs to be rotated
- Landing-gear bay to be realized in a way that is representative of real acoustics
were taken into account upfront and did not lead to a design solution that would impact either test.
Within EASIER the test-setup was defined and tested in the WT in an isolated environment. A setup including sideline microphones, a beamforming array and specific locations to position the array was defined and validated during the pre-tests. As model during the pre-test a microphone was used, thus allowing generating a defined noise and making sure that the post-procession actually works. The pre-test was successfully performed, important lessons learned for the main test were obtained.
After model availability the tests were performed in the RUAG-Wind-Tunnel using a test-matrix defined together with the Topic Manager. The Wind-Tunnel tests were performed as planned, allowing a characterization of the noise acting on the wing and analyzing the effect of low-noise technologies developed within the GRA ITD..


Project Context and Objectives:
Nowadays, the application of the Natural Laminar Flow (NFL) technology becomes more and more attractive since it offers the possibility to match the ACARE requirements in terms of reducing fuel consumption and pollution at cruise flight condition, but ACARE requirements claim also for an overall aircraft noise reduction.
Laminar flow technology offers significant advantages in terms of fuel burn and CO2 emission in cruise condition, but an aircraft flies also in off design, landing and take-off conditions where the performance of a natural laminar aircraft shows some critical aerodynamic issues and noise emission becomes very important. The aerodynamic issues arise from the need to have a clean leading edge and by the fact that a trailing edge high lift system is not able to ensure the ClMAX for landing and take-off conditions. In addition, the laminar flow coverage can be negatively affect by the insect contamination and by the icing expected during take-off and low-altitude operation. The implementation of a Krueger flap become mandatory since it can overcome this problem because it allows obtaining the necessary lift for the landing and simultaneously protecting the leading edge from the contamination of the insects and ice, even if it can limit the laminar flow only to the suction wing side. In addition, Krueger flaps offer the advantage that only the pressure surface of the cruise airfoil is affected by the integration of the leading edge device, and the resulting surface steps and gaps, into the cruise wing. The lack of surface discontinuities on the suction surface has made the Krueger flap as the most promising leading-edge device for laminar flow wing designs as illustrated by the study of Moens and Capbern. But, this high lift device, when deployed, could have also a negative impact on the overall aircraft performances due to coherent structures as strong eddies generated in the leading edge region and responsible of tonal noise emission. Another aspect that can affect not only the extension of the laminar flow on the wing but also the acoustic performance of the aircraft is the location and the installation of the engines. In particular, the installation with under wing engines may present some problems from the laminar flow point of view, because the flow that invests the wing leading edge will interact with the nacelle and the pylon and this can generate disturbances that are swallowed by the boundary layer triggering premature transition and consequently generating noise. For this reason, a very efficient installation of the propulsion system could be the aft-engine arrangements, because this solution excludes any type of interference between the laminar boundary layer on the wing, the pylon and the nacelle. Further improvements to the aerodynamic efficiency of this future laminar aircraft can be achieved by reducing the lift-induced drag by increasing the aspect ratio of the wing. This has been done by developing wing tip devices acting on the tip vortex which is at the origin of the lift-induced drag. Basic studies have shown that drag reduction can be obtained with variations in planform geometry along a small fraction of the wing-span and with aft-swept configurations. The Green Regional programme of the “Clean Sky” Joint Technology Initiative is developing the future green regional aircraft configuration including the above mentioned laminar flow technologies. But what about the acoustic impact of these devices on the aircraft overall noise? Is an optimized aerodynamic configuration an optimum from the acoustic point of view? Is it possible to identify an A/C configuration having a good behaviour from both aerodynamic and acoustic point of view?
Within this context, Aircraft noise is getting a major interest by the scientific community due to the effort in reducing sky-traffic acoustic pollution in the airport area. Aircraft landing gear, propeller and high lift devices (HLD) have been recognized in recent years as responsible of the major contributors to the total aircraft noise, especially at landing and take-off conditions. After a period of improvements on low noise engines, the attention has been, nowadays, shifted on the study of the airframe aerodynamics. This is particularly challenging because of the large interaction between the slipstream generated by the engine and wings/airframe and between the landing gears and fuselage
Modern computation methods are mainly based on ideal fluid theory, and are not able to fully reveal and take into account the above-mentioned effects. Therefore, the numerical prediction of these sources of noise remains one of the most difficult challenges in aero-acoustics, because of the complexity of the gear and propeller geometries and the surrounding flow field. Experimental activities are, therefore, the main way to study the acoustic performances of propellers and airframe/landing gears interaction, to assess the magnitude of the noise sources and to develop an analytical and experimental data base for numerical comparisons.
Experimental tests on geared turbofan configurations typically use unpowered engines providing only partial information of the acoustic performance of the aircraft without considering the interactions between the propulsion system and both the airframe and aerodynamic surfaces (wings, HLD, fuselage and empennage). To provide more accurate experimental estimates of the overall acoustic performances, challenging experimental tests using active engines are necessary.
The main innovative aspect of the EASIER project is the noise assessment of a geared turbofan Regional Aircraft by mean of wind tunnel tests on a complete and powered aircraft Model. A further innovative aspect of the project regards the assessment of the innovative “power Plant Integration” architecture in noise reduction. At this aim, tests are planned on the model with different Power Plant Configurations:
• To evaluate at take-off and landing conditions the whole A/C noise emission in far-field on a polar arc microphone array;
• To identify in the same conditions the noise sources by means of a beamforming technique and their contribution to the emitted noise.
• Verify the power plant integration, engine location, empennages sizing & position and wing tip-concepts optimization from an acoustic point of view, compared to the baseline configuration;
In order to fulfill these goals, the EASIER project can be split in the following technical activities:
I. Model modifications to fulfill WT requirements for acoustic tests.
II. FEM model creation and Validation
III. WT Tunnel instrumentation definition
IV. WT test campaign.
V. Data analysis & post-processing
Project Results:
Main S&T results/ foreground
The following scientific and technical results have been identified:
Scientific:
- University of Rome 3 has developed a method that allows calculating correct EPNL from test-results obtained by closed-wall wind tunnels. This is a very innovative solution for the problem of noise characterisation and allows using closed-wall WT in the future. The advantage of this approach is that these WT are less costly than dedicated WTs and have a higher availability.
Technical:
- Within EASIER technologies have been developed on how to perform noise-characterisations on powered WT-models. Although during the WT-tests the engine in EASIER was not running (due to requirements from the Topic Manager) it is possible and allows an improved acoustic result.
- In EASIER there was a need to quickly rotate the model after the aerodynamic test campaign to implement it into the acoustic configuration. This was realised after strong discussions with RUAG in a very efficient way, reducing the WT-blocking time and improving in total the output.
- EASIER performed the noise-assessment for the flap-fence technology developed in the CS-GRA ITD. It can be seen that the application of the flap-fence is able to reduce the noise omitted during the landing/ takeoff phase.

Potential Impact:
Impact:
EASIER was set up between partners to first of all create impact on the partners itself, impact the GRA-ITD and the European research as well as industrial community.
Bringing together a complementary consortium, in terms of competencies, of two SMEs and a university, allows for commonalities to be identified and opens the possibility for cross-domain sharing of concepts, methods and tools in order to enable reusable embedded technology development. In addition, the consortium EASIER uses one of the largest European Wind Tunnel with extensive experience in mechanical design of aircraft models, in development of hydraulic motors and in aerodynamic and aero-acoustic testing. These transversal competences, added to the specific competences of the involved SMEs, enables the consortium to be extremely confident in solving any critical problem that requires interdisciplinary expertise, thus allowing EASIER to address any technological innovation and/or any new model. The cooperation between the different partners enriched their knowledge and their capabilities in design and manufacturing and testing. Furthermore, the assessment of acoustic measurements for powered geared turbofan models will increase wind tunnel competencies on acoustic measurements and setup, so that, higher services and support will be provided to all European aeronautical industries. This allows increasing the competitiveness of the European aeronautical industries in the world.
The impact of this project will work on several different levels:
• Regarding GRA JTI-Cleansky this project will help in solving important questions about the noise emission in landing and takeoff flight conditions. In fact, the project investigates the acoustic performance of high lift devices more appropriate for wings showing laminar flow and their application on future Green Regional Aircraft (Krueger and innovative trailing edge). On an international level this increases Europe’s competitiveness in the development of the future natural laminar aircrafts, since the landing and take-off flight conditions are strongly affected by these devices. Natural laminar flow technology without appropriate high lift system cannot be used. The optimization of winglets, from the aerodynamic and acoustic point of view, will contribute to further decrease the drag, by reducing the induced lift, and the noise emission by eliminating interferences. As consequence both technologies lead to reduced fuel burn by
o reducing drag (NLF)
o reducing weight (LC&A)
and are therefore in line with the ACARE-goals
• Apart from that on national level each partner that contributed to the project has several advantages:
o Insight into high fidelity test results for an advanced technology aircraft wing
o A reference project that shows competence on an international level as well as successfully working together as a multi-disciplinary team
o All partners in the consortium have the opportunity to further increase their know-how by working in synergy and in an international context. In case of the SMEs this can be further exploited by transferring IP generated in this project into industrial applications. The research facilities strengthen their competence in their field of work.
o The SMEs IBK and EUROTECH strongly interacted with one of the largest European Wind Tunnel (RUAG) and this provided a formidable chance to enrich their expertise
• RUAG wind tunnel improved their competencies in acoustic testing

This will contribute to increase the competitiveness of the European aeronautical industries because they will have a facility that can also simulate acoustic performance in landing and take-off conditions by using engine simulators for turbo fan aircraft configurations.

Socio-Economic Impact/ Wider societal impact:
Due to the strong technical focus of this project the direct socio-economic impact of this project is limited.
Indirect IBK as well as EUROTECH as SME´s are seeing gender equality as one of the relevant topics for their human-resource strategy. Within IBK ~30% of the employees are female (seen over all technical units). Apart from that IBK is very supportive in enabling work-life balance, especially supporting young families with part-time jobs. This helps to keep young and very skilled professionals in the company, provides a good internal climate and a forward oriented mind-set.
Being able to positively support these projects as SME is therefore supporting IBK´s and EUROTECH´s strategies.
Exploitation:
All work packages undergo an internal checks from each partner for exploitation. The management of knowledge and intellectual property, as well as the establishment of exploitation and dissemination strategies are dedicated
− To manage the generated knowledge and confidentially-related issues.
− To identify the results that can be disseminated (through publications, conferences, workshops, technology transfers)
− To identify results that should be protected (through patents, copyrights or secret) and - if necessary - to achieve an agreement in case of joint ownership.
− To analyse end-user requirements and a potential market as an exploitation strategy.
− Intellectual Property Rights and dissemination of knowledge are not incompatible, provided that they are based on clear principles and rules.
Ownership of results, mutual granting of access rights, IP protection (including patenting) and licensing policy are defined in a Consortium Agreement between the three participants.
Currently the following items have been identified for further exploitation:
- University of Rome has developed a method that allows calculating correct EPNL from test-results obtained by closed-wall wind tunnels. This is a very innovative solution for the problem of noise characterisation and allows using closed-wall WT in the future. The advantage of this approach is that these WT are less costly than dedicated WTs and have a higher availability.
- Within EASIER technologies have been developed on how to perform noise-characterisations on powered WT-models. Although during the WT-tests the engine in EASIER was not running (due to requirements from the Topic Manager) it is possible and allows an improved acoustic result.
- In EASIER there was a need to quickly rotate the model after the aerodynamic test campaign to implement it into the acoustic configuration. This was realised after strong discussions with RUAG in a very efficient way, reducing the WT-blocking time and improving in total the output.
List of Websites:
No website was installed for the project EASIER
Contact Details for Coordinator are:
Stephan Adden
IBK-Innovation GmbH & Co. KG
Butendeichsweg 2
21129 Hamburg

Reported by

IBK-INNOVATION GMBH & CO. KG
Germany
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top