City Research Online

Passive control of the flow around unsteady aerofoils using a self-activated deployable flap

Rosti, M. E., Omidyeganeh, M. & Pinelli, A. (2018). Passive control of the flow around unsteady aerofoils using a self-activated deployable flap. Journal of Turbulence, 19(3), pp. 204-228. doi: 10.1080/14685248.2017.1314486


Self-activated feathers are used by many birds to adapt their wing characteristics to the sudden change of flight incidence angle. In particular, dorsal feathers are believed to pop-up as a consequence of unsteady flow separation and to interact with the flow to palliate the sudden stall breakdown typical of dynamic stall. Inspired by the adaptive character of birds feathers, some authors have envisaged the potential benefits of using of flexible flaps mounted on aerodynamic surfaces to counteract the negative aerodynamic effects associated with dynamic stall. This contribution explores more in depth the physical mechanisms that play a role in the modification of the unsteady flow field generated by a NACA0020 aerofoil equipped with an elastically mounted flap undergoing a specific ramp-up manoeuvre. We discuss the design of flaps that limit the severity of the dynamic stall breakdown by increasing the value of the lift overshoot also smoothing its abrupt decay in time. A detailed analysis on the modification of the turbulent and unsteady vorticity field due to the flap flow interaction during the ramp-up motion is also provided to explain the more benign aerodynamic response obtained when the flap is in use.

Publication Type: Article
Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Turbulence on 13/04/2017, available online:
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments: School of Science & Technology > Engineering
SWORD Depositor:
[thumbnail of jotrosti.pdf]
Text - Accepted Version
Download (11MB) | Preview


Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Downloads per month over past year

View more statistics

Actions (login required)

Admin Login Admin Login