Feedback Control Using Extremum Seeking Method for Drag Reduction of a 3D Bluff Body

  • Jean-François Beaudoin
  • Olivier Cadot
  • José Eduardo Wesfreid
  • Jean-Luc Aider
Part of the IUTAM Bookseries book series (IUTAMBOOK, volume 7)


The flow around a modified Ahmed body with a curved rear section is studied at Re > 2.106 and a line of vortex generators (VG) is used as actuators. By varying the angle α of the VG we observe an optimal value of α defining a minimum of aerodynamic drag and correspondingly a maximum base pressure coefficient. As this optimum value is shown to be Reynolds dependent we use an extremum control strategy for the system to find this optimal condition autonomously. It consists of the synchronous detection of the response measured in either the base pressure signal or in the drag and a slow sinusoidal modulation of the angle of the VG. It is finally demonstrated that the closed-loop system is robust and reacts successfully to unpredictable changes in the external flow conditions.

Key words

Feedback loop control drag reduction 


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Copyright information

© Springer 2008

Authors and Affiliations

  • Jean-François Beaudoin
    • 1
  • Olivier Cadot
    • 2
  • José Eduardo Wesfreid
    • 3
  • Jean-Luc Aider
    • 1
  1. 1.Department of Research and InnovationPSA Peugeot-CitroënVélizy-VillacoublayFrance
  2. 2.Unité de MécaniqueENSTAPalaiseauFrance
  3. 3.PMMH UMR 7636-CNRS-ESPCIParis Cedex 5France

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