Experiments in Fluids

, 58:103 | Cite as

Drag reduction of a car model by linear genetic programming control

  • Ruiying Li
  • Bernd R. Noack
  • Laurent Cordier
  • Jacques Borée
  • Fabien Harambat
Research Article


We investigate open- and closed-loop active control for aerodynamic drag reduction of a car model. Turbulent flow around a blunt-edged Ahmed body is examined at \(Re_{H}\approx 3\times 10^{5}\) based on body height. The actuation is performed with pulsed jets at all trailing edges (multiple inputs) combined with a Coanda deflection surface. The flow is monitored with 16 pressure sensors distributed at the rear side (multiple outputs). We apply a recently developed model-free control strategy building on genetic programming in Dracopoulos and Kent (Neural Comput Appl 6:214–228, 1997) and Gautier et al. (J Fluid Mech 770:424–441, 2015). The optimized control laws comprise periodic forcing, multi-frequency forcing and sensor-based feedback including also time-history information feedback and combinations thereof. Key enabler is linear genetic programming (LGP) as powerful regression technique for optimizing the multiple-input multiple-output control laws. The proposed LGP control can select the best open- or closed-loop control in an unsupervised manner. Approximately 33% base pressure recovery associated with 22% drag reduction is achieved in all considered classes of control laws. Intriguingly, the feedback actuation emulates periodic high-frequency forcing. In addition, the control identified automatically the only sensor which listens to high-frequency flow components with good signal to noise ratio. Our control strategy is, in principle, applicable to all multiple actuators and sensors experiments.



The authors acknowledge the great support during the experiment by J.-M. Breux, J. Laumonier, P. Braud and R. Bellanger. The thesis of RL is supported by the OpenLab Fluidics between PSA Peugeot-Citroën and Institute Pprime (Fluidics @ poitiers). We appreciate valuable stimulating discussions with: Markus Abel, Diogo Barros, Steven Brunton, Eurika Kaiser, Siniša Krajnović, Vladimir Parezanović, Rolf Radespiel, Peter Scholz, Richard Semaan, Andreas Spohn and Mattias Wahde.


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Copyright information

© Springer-Verlag GmbH Germany 2017

Authors and Affiliations

  1. 1.Institut PPRIMECNRS-Université de Poitiers-ISAE-ENSMAChasseneuil-du-PoitouFrance
  2. 2.LIMSI-CNRSOrsay cedexFrance
  3. 3.Technische Universität BraunschweigBraunschweigGermany
  4. 4.Institut für Strömungsmechanik und Technische Akustik (ISTA)Technische Universität BerlinBerlinGermany
  5. 5.PSA Peugeot CitroënCentre Technique de VélizyVélizy-VillacoublayFrance

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