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EU research results

CORDIS

Drag Reduction in Turbulent Boundary Layer via Flow Control

Fact Sheet

Result in Brief

Reporting

Results

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Spain

Objective

The proposed project “Drag Reduction via Turbulent Boundary Layer Flow Control” (DRAGY) will approach the problem of turbulent drag reduction through the investigation of active/passive flow-control techniques to manipulate the drag produced by the flow structures in turbulent boundary layers. In addition, the project aims to improve the understanding of the underlying physics behind the control techniques and its interaction with the boundary layer to maximize their efficiency.
Turbulent Boundary Layer Control (TBLC) for skin-friction drag reduction is a relatively new technology made possible through the advances in computational-simulation capabilities, which have improved our understanding of the flow structures of turbulence. Advances in micro-electronic technology have enabled the fabrication of actuation systems capable of manipulating these structures. The combination of simulation, understanding and micro-actuation technologies offer new opportunities to significantly decrease drag, and by doing so, increase fuel efficiency of future aircraft. The literature review that follows will show that the application of active control turbulent skin-friction drag reduction is considered of prime importance by industry, even though it is still at a very low Technology Readiness Level (TRL =1). Given the scale of the “Flightpath 2050” challenge, now is the appropriate time to investigate the potential of this technology and attempt to raise the TRL to 2 or possibly 3 in some particular branches of the subject. DRAGY proposes a European R&T collaborative effort specifically focused on active and passive control for turbulent skin-friction drag reduction.
The project will result in mutual benefits for industry and scientific European as well as Chinese communities, in a topic of growing concern, namely drag-reduction technologies.

Field of Science

aircraft

literature - general

Programme(s)

H2020-EU.3.4. - SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Topic(s)

MG-1.10-2015 - International cooperation in aeronautics with China

Call for proposal

H2020-MG-2015_SingleStage-A

See other projects for this call

Funding Scheme

RIA - Research and Innovation action

Leaflet | Map data © OpenStreetMap contributors, Credit: EC-GISCO, © EuroGeographics for the administrative boundaries

Coordinator

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Address

C Gran Capitan, Edifici C1, Campus Nord Upc Sn
08034 Barcelona

Spain

Activity type

Research Organisations

EU Contribution

€ 220 000

Website

Contact the organisation

Participants (12)

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UNIVERSIDAD POLITECNICA DE MADRID

Spain

EU Contribution

€ 265 000

THE UNIVERSITY OF SHEFFIELD

United Kingdom

EU Contribution

€ 185 000

DEUTSCHES ZENTRUM FUER LUFT - UND RAUMFAHRT EV

Germany

EU Contribution

€ 276 075

OFFICE NATIONAL D'ETUDES ET DE RECHERCHES AEROSPATIALES

France

EU Contribution

€ 80 145

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS

France

EU Contribution

€ 221 500

IMPERIAL COLLEGE OF SCIENCE TECHNOLOGY AND MEDICINE

United Kingdom

EU Contribution

€ 219 996

CHALMERS TEKNISKA HOEGSKOLA AB

Sweden

EU Contribution

€ 80 000

POLITECNICO DI MILANO

Italy

EU Contribution

€ 150 000

AIRBUS GROUP LIMITED

United Kingdom

EU Contribution

€ 50 709

AIRBUS OPERATIONS SL

Spain

EU Contribution

€ 25 000

DASSAULT AVIATION

France

EU Contribution

€ 24 970

AIRBUS OPERATIONS LIMITED

United Kingdom

EU Contribution

€ 29 291

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Spain

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

DE EN ES FR IT PL

Towards more energy-efficient aircraft

An emphasis on reducing the environmental impact of aircraft means EU-funded scientists have been researching ways to reduce drag using an aircraft’s small, active components to make them more energy-efficient and reduce emissions.

TRANSPORT AND MOBILITY

INDUSTRIAL TECHNOLOGIES

Reductions in carbon dioxide and nitrogen oxide emissions from aircraft are directly related to an aircraft’s fuel burn, drag and aircraft weight. So reducing surface drag – which impedes forward movement during flight – will help reduce the environmental impacts of harmful emissions. “It is not just the shape of the airframe but also some devices which act on the flow field that determines drag,” says DRAGY project coordinator Gabriel Bugeda, Professor of Civil and Environmental Engineering at the International Centre for Numerical Methods in Engineering (CIMNE), at the Technical University of Catalunya (UPC), in Barcelona, Spain. Some of the most promising devices identified at the beginning of the project were analysed in laboratory experiments using numerical analysis based on new computational-simulation technologies to analyse flow structures. “We analysed alternatives for drag reduction using active devices that require some energy to operate, such as rotating disks, pulsing jets and even riblets,” Bugeda says. Riblets are ribbed surfaces in the direction of airflow which can reduce resistance compared to smooth surfaces.

Devices that can reduce drag

Riblets, and other devices such as plasma actuators, where a small amount of air is injected into the flow field using plasma devices, can reduce drag. “These are the two most promising devices,” says Bugeda, adding that pulse jets, which inject a specific amount of fluid in a pulsating action rather than steady stream, and rotating discs, to inject additional momentum of fluid, also have potential. “We arrived at the conclusion that some of these devices can produce up to 40 % surface drag reduction – so this is new – but it is still at a very low level of technological development,” notes Bugeda. Nonetheless, with fuel costs at least 30 % of a commercial aircraft’s operating costs, it could represent a significant saving. “An aeroplane would have a large number of these devices distributed through the fuselage or the wing,” Bugeda explains. But there is also a payoff because: “These devices have some weight and need some energy to work and we have not yet evaluated the ‘cost’ of these, but it is nonetheless a significant finding.” In addition to the engines and other parts of the aircraft, conventional configurations are now close to full optimisation. “But we have confirmed in the laboratory that by looking at these devices, improvements can still be made,” Bugeda notes.

Scaling up

Scaling up is still a major challenge. “These devices act on the flow field in a very small area,” Bugeda notes. “It is not easy to extrapolate the results of these [laboratory scale] experiments to real-sized aircraft. So the experiments need to be as close as possible to real size, which is not always possible in the laboratory.” As the project is a collaboration between European institutions and China, with the costs in China covered by the Ministry of Industry and Information Technology in Beijing, the project was able to take advantage of large-scale experimental facilities at Zhejiang University, Northwestern Polytechnical University, Peking University and Beijing University of Aeronautics and Astronautics. For the numerical analysis, the main difficulty is the amount of computer power needed, Bugeda explains. “It is not yet market ready,” Bugeda says, noting that future collaboration projects would further develop such technologies for use in real aircraft.

Keywords

DRAGY, aircraft, China, drag, energy-efficient, emissions, riblets, aerodynamic, airflow, pulse jets, carbon dioxide, nitrogen oxide

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

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Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Spain

Periodic Reporting for period 1 - DRAGY (Drag Reduction in Turbulent Boundary Layer via Flow Control)

Reporting period: 2016-04-01 to 2017-09-30

Summary of the context and overall objectives of the project

DRAGY project approaches the problem of turbulent drag reduction through the investigation of active/passive flow-control techniques to manipulate the drag produced by the flow structures in turbulent boundary layers. In addition, making use of new algorithms and exploiting efficiently large computing facilities, the project aims to improve the understanding of the underlying physics behind the control techniques and its interaction with the boundary layer to maximize their efficiency.

Turbulent Boundary Layer Control for skin-friction drag reduction is a relatively new technology made possible through the advances in computational-simulation capabilities, which have improved our understanding of the flow structures of turbulence. Advances in micro-electronic technology have enabled the fabrication of actuation systems capable of manipulating these structures. The combination of simulation, understanding and micro-actuation technologies offer new opportunities to significantly decrease drag, and by doing so, increase fuel efficiency of future aircraft. The literature review shows that the application of active control turbulent skin-friction drag reduction is considered of prime importance by industry, even though it is still at a very low TRL. Given the scale of the “Flightpath 2050” challenge, now is the appropriate time to investigate the potential of this technology and attempt to raise the TRL in some particular branches of the subject. DRAGY is a Europe-China R&T collaborative effort specifically focused on active and passive control for turbulent skin-friction drag reduction.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The technical achievements reported in the mid-term report show that the technical programme is developing along the projected planned activities and objectives lines. The main conclusions after this reporting period are the following:

- More than one technique for drag reduction is showing interesting results. The common adoption of the CPI framework will allow a straightforward comparison among the benefits of the various techniques. The progress is not only observed in detailed numerical simulations but also in setting up experiments for measuring their effectiveness in the wind tunnel.

- An important problem which is still under discussion is the availability of a reliable, feasible and reasonably accurate strategy for measuring drag for actuated flow experimental test.

- Efforts directed towards jet-based actuation have not yet yielded any pertinent information on outer-inner interactions. There is then needs to work on establishing an obvious rational foundation for a cohesive programme that involves the selection of actuation parameters and the characterization of the effectiveness of such actuation in the context of examining outer-inner interactions. The experimental programme of DLR with synthetic slot jets is expected to commence in December 2017.

- Work related to boundary layer outer structure has identified the important role played by the outer structures on the Reynolds stresses, and skin friction, and has demonstrated major differences between the effects of high-speed and low-speed outer motions on the properties of the near-wall streaks and the skin friction. Despite the rich insight derived from the analysis, a quantitative statement on the effects of large-scale structures on the skin friction is not possible without the imposition control on the outer structures.

- EMD in combination with the Hilbert transport to analyse temporal data arising from DNS, in cases for canonical channel flow has so far demonstrated its ability to characterize, qualitatively, the correlation between large-scale motions and the envelope of the small-scale motions, which indicate small-scale modulation. This work will be extended to include actuated flows.

- A large number of simulations at one low Reynolds number are performed and others at higher values are progressing. Results so far appear to demonstrate that filtering out the outer and intermediate structures in the log-law region by restricting the size of the simulation box has a significant effect on the drag and its reduction. Studies at higher Reynolds numbers are important as the role of large scales only becomes significant at higher Reynolds numbers.

- Currently there are a lot of activities concerning the development of the decision matrix for selecting the most promising actuation method and technology. Thus, the first focal point of the activity in WP4 so far has been the preparation of the evaluation matrix of test facilities, flow conditions, flow actuation types and measurements types. The second focal point has been some preparative wind tunnel tests on industrial level, which are necessary for the demonstration of the selected technologies for drag reduction.

- An initial specification of actuation parameters for active control of near wall turbulence has been obtained for medium and long range civil transports in cruise based on RANS computations for representative fuselage configurations. This currently neglects any Reynolds number effects and is just the first attempt based on the information currently available from the literature. From the literature search on turbulence models it has been found the effect of riblets on a boundary layer can be captured through modified forms of the Spalart Allmaras and Wilkox k-ω turbulence models that result in a wall normal displacement in the law of the wall profile.

- A riblet model has been implemented in two different RANS solvers and validation is in progress. This forms the basis for model modif

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

DRAGY is making a significant contribution to improve the performance of new aircraft. It will deliver a major step forward in the design of novel configuration aircraft which will have reduced operating costs and lower emissions than today’s standard of aircraft due to the reductions in fuel burn brought about by lower viscous drag levels. In this way the consortium will help to maintain the steady growth that industry is currently demonstrating and ensure that the European aeronautics industry retains its competitive edge.

DRAGY project will contribute to the European goal to make transport growth and sustainability compatible, by decoupling environmental impacts from economic growth, while assuring the competitiveness and the innovative character of the European transport industry. The project brings together world-class experts in the specific technology areas with the aim of delivering the breakthrough in flow control technology focused on skin friction drag reduction. The consortium, consisting of universities, research organisations and industry, ensures that the created knowledge is exploited by industry and is available to the wider community for education purposes.

DRAGY addresses this issue by identifying technologies that could be matured and incorporated into a commercial aircraft utilising flow control to target the viscous drag component of total drag. Such an aircraft could have 10% higher cruise lift-to-drag ratios than an equivalent aircraft without flow control. In addition the Turbulent Skin Friction Drag Reduction technology investigated within DRAGY may be appropriate for retrofitting on existing aircraft. It is not necessarily reliant on the adoption of a novel configuration.

Sketch of drag reduction devices: geometry modification (riblets), spanwise forcing at the wall, jet

Concept of aircraft drag forces and drag reduction potential analysis

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

Spain

Project information

DRAGY

Grant agreement ID: 690623

Project website

Status

Closed project

Start date

1 April 2016
End date

30 June 2019

Funded under:

H2020-EU.3.4.

Overall budget:

€ 1 827 686,25
EU contribution

€ 1 827 686

Coordinated by:

CENTRE INTERNACIONAL DE METODES NUMERICS EN ENGINYERIA

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Last update: 28 June 2019

Record number: 199572

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Participants (12)

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Towards more energy-efficient aircraft

Devices that can reduce drag

Scaling up

Keywords

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Periodic Reporting for period 1 - DRAGY (Drag Reduction in Turbulent Boundary Layer via Flow Control)

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CORDIS

Project information

Objective

Coordinator

Participants (12)

Project information

Project information

Towards more energy-efficient aircraft

Devices that can reduce drag

Scaling up

Keywords

Project information

Discover other articles in the same domain of application

Project information

Periodic Reporting for period 1 - DRAGY (Drag Reduction in Turbulent Boundary Layer via Flow Control)

Project information

Project information

Deliverables

Publications

Project information

Project information

Project information

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