On the effect of sweep on separation control

Philipp Tewes, Lutz Taubert, Israel Wygnanski

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The performance of a flapped wing based on a NACA 0012 airfoil section and equipped with a linear array of fluidic oscillators was investigated experimentally to assess the significance of wing sweep and aspect ratio on the efficiency of the actuation. The semi-span wing that was suspended from the wind tunnel ceiling through a six-component balance could be withdrawn partially from the test section and rotated in a plane parallel to the flow thus its sweep could vary from 0° to ±45° and its aspect ratio could change from 2.4 to 7.5. The wing incidence, its flap deflection, and the level and distribution of the actuation were the additional independent parameters investigated. The experiments were carried out at Reynolds numbers varying between 300,000 and 500,000. The boundary layer was tripped in order to fix the location at which transition to turbulence occurs. To overcome separation at high flap deflections in the absence of wing sweep, a minimum momentum coefficient of the order of 1% was required. However, on a swept-back wing a substantially lower input level could improve the lift generated by the wing by some 20% and alter the pitching moment provided the aggregate number of the actuators was small. Under these conditions, the actuators acted as fluidic boundary layer fences that can be switched ON or OFF on demand and change the aerodynamic characteristics of the wing for takeoff and landing purposes. An attempt was made to explain the mechanism that makes the fluidic oscillators so effective.

Original languageEnglish
Title of host publicationAIAA AVIATION 2014 -7th AIAA Flow Control Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781624102929
StatePublished - 2014
Externally publishedYes
EventAIAA AVIATION 2014 -7th AIAA Flow Control Conference 2014 - Atlanta, GA, United States
Duration: 16 Jun 201420 Jun 2014

Publication series

NameAIAA AVIATION 2014 -7th AIAA Flow Control Conference


ConferenceAIAA AVIATION 2014 -7th AIAA Flow Control Conference 2014
Country/TerritoryUnited States
CityAtlanta, GA


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