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1 Flexible flaps for separation control on a wing with low aspect ratio Dipl. Ing. G. Patone Dr. W. Müller Dr. R. Bannasch Prof. Dr. Ing. I. Rechenberg.

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Presentation on theme: "1 Flexible flaps for separation control on a wing with low aspect ratio Dipl. Ing. G. Patone Dr. W. Müller Dr. R. Bannasch Prof. Dr. Ing. I. Rechenberg."— Presentation transcript:

1 1 Flexible flaps for separation control on a wing with low aspect ratio Dipl. Ing. G. Patone Dr. W. Müller Dr. R. Bannasch Prof. Dr. Ing. I. Rechenberg

2 2 bionics pilot project: Aeroflexible surface flaps as "eddy-breaks" built after the covert feathers of birds Project partners: DLR Abt. Turbulenzforschung Firma Stemme GmbH Fachgebiet Bionik und Evolutionstechnik an der TU-Berlin

3 3 main objective: eddy

4 4 Brown Skua with eddy-flaps lifted covert feathers eddy- flaps eddy

5 5 aerofoil with eddy- flaps eddy- flaps

6 6 cLcL goal: not like thisbut like this cLcL cLcL cLcL cDcD cDcD

7 7 research goal improving the stall behavior of an aerofoil flaps should not have any negative effects while not active flaps should work without external controls

8 8 experimental setup at the wind tunnel lift-balance wind tunnel 10m/s drag-balancepressure sensor and scanivalve NACA 2412 aerofoil with an aspect ratio of 3.5 R e =

9 9 porosity schematic pressure distribution p x > p y impervious materials are lifted off by the pressure differences porous materials remain on the surface

10 10 aerofoil with silk flaps silk steel wire

11 11 silk flaps

12 12 polar diagram for perforated plastic sheet flaps

13 13 aerofoil for pressure distribution

14 14 pressure distribution at 16 degrees incident airflow without flaps with flaps

15 15 pressure distribution at 19 degrees incident airflow without flaps with flaps

16 16 flow visualisation trapped vortextrapped eddy

17 17 pressure distribution at 36 degrees incident airflow without flaps with flaps

18 18 polar diagram (calculated from all measuring rows)

19 19 lift distribution without flaps at different angles of attack

20 20 lift distribution with flaps at different angles of attack

21 21 summary: eddy flaps prevent sudden drop in lift generation during stall pressure distribution indicates: eddy-flaps restrict eddy to hind part of aerofoil outlook: automatic contour adapting flaps dynamic stall behaviour


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