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Active flow separation control at the outer wing


Within the European project AFLoNext, one of the technological streams is dedicated to the investigation of active flow control (AFC) to increase the robustness of the wing tip design at takeoff conditions, whilst allowing the optimization of aerodynamic efficiency in cruise. AFC is used to delay the wing tip stall, which is caused by vortex breakdown, thus improving the lift to drag ratio and allowing a steeper climb gradient during second segment climb when the landing gear is retracted. The numerical parametric studies of AFC aerodynamic sizing were shared between the involved partners on the basis of actuator location (in the leading edge region or on the upper surface) and actuator types (steady blowing, synthetic jets, pulsed jets). Most of the numerical results have been obtained for steady blowing through continuous or segmented slots. The specific effect of the unsteady means of actuation on the flow topology was also identified. The aim of this study was to take into account industrial requirements defined by Airbus and geometric constraints of AFC actuators arising from the project partners involved in the development of AFC hardware. Some comparisons between the partners’ results are presented, allowing preliminary conclusions to be drawn. The most effective and efficient device turned out to be pulsed blowing through segmented slots located at the leading edge separation line.

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α :

Angle of attack

C D :

Drag coefficient


Longitudinal skin friction coefficient

C L :

Lift coefficient

C m :

Pitching moment coefficient


Blowing momentum coefficient based on wing reference surface


Pressure coefficient

L/D :

Lift to drag ratio

Q :

Second invariant of the velocity gradient tensor


Active flow control


Angle of attack


Computer aided design


Computational fluid dynamics


Improved delayed detached eddy simulation


Leading edge


Large eddy simulation


Pulsed jet actuator


Reynolds average Navier–Stokes


Synthetic jet actuator


Technology stream


Ultra-high bypass ratio


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The work described in this paper and the research leading to these results have received funding from the European Community’s Seventh Framework Programme FP7/2007-2013, under Grant agreement n° 604013, AFLONEXT project.

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Correspondence to J. P. Rosenblum.

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This paper is part of a Special Issue on the AFLoNext project, funded by the European Union's FP7 under grant agreement No 604013.

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Rosenblum, J.P., Vrchota, P., Prachar, A. et al. Active flow separation control at the outer wing. CEAS Aeronaut J 11, 823–836 (2020).

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  • Flow separation control
  • Wing tip
  • CFD