Advertisement

Effects of Unsteady Coanda Blowing on the Wake and Drag of a Simplified Blunt Vehicle

  • D. BarrosEmail author
  • J. Borée
  • B. R. Noack
  • A. Spohn
  • T. Ruiz
Chapter

Abstract

The impact of periodic forcing on the wake past a square back bluff body is experimentally studied. By the use of pulsed jets in combination with a Coanda effect, shear layer forcing allows to recover over 30 % of the model’s base pressure. The actuation frequency is an order of magnitude higher than the natural flow instabilities. Velocity measurements indicate that this direct wake control modifies the vorticity development along the shear layers and shrinks the width of the recirculating flow region down. At the same time, the velocity fluctuations in the near wake decrease, without measurable impact on the oscillatory vortex shedding. With this control strategy, both the flow deviation and the base pressure recovery are dependent on the upstream Reynolds number. Particle image velocimetry data and pressure measurements are used to discuss the origin of these observations.

Keywords

Particle Image Velocimetry Shear Layer Strouhal Number Bluff Body Rear Surface 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

The thesis of D.B is supported financially by PSA—Peugeot Citroën and ANRT in the context of the OpenLab Fluidics between PSA - Peugeot Citroën and Institut Pprime (fluidics@poitiers). The authors acknowledge the funding of the Chair of Excellence - Closed-loop control of turbulent shear flows using reduced-order models (TUCOROM)- supported by the French Agence Nationale de la Recherche (ANR). We warmly thank the support during the experiments by J.M. Breux.

References

  1. 1.
    S.R. Ahmed, G. Ramn, G. Faltin, Some salient features of the time averaged ground vehicle wake. SAE Technical Report. No. 840300, Society of Automotive Engineers Inc., Warrendale, PA (1984)Google Scholar
  2. 2.
    M. Grandemange, M. Gohlke, O. Cadot, Turbulent wake past a three-dimensional blunt body. Part 1. Global modes and bi-stability. J. Fluid Mech. 722, 51–84 (2013)Google Scholar
  3. 3.
    H. Choi, J. Lee, H. Park, Aerodynamics of heavy vehicles. Ann. Rev. Fluid Mech. 46, 441–468 (2014)MathSciNetCrossRefzbMATHGoogle Scholar
  4. 4.
    P. Huerre, P.A. Monkewitz, Local and global instabilities in spatially developing flows. Ann. Rev. Fluid Mech. 22 (1), 473–537 (1990)MathSciNetCrossRefzbMATHGoogle Scholar
  5. 5.
    H. Choi, W.P. Jeon, J. Kim, Control of flow over a bluff body. Ann. Rev. Fluid Mech. 40, 113–139 (2008)MathSciNetCrossRefzbMATHGoogle Scholar
  6. 6.
    R.J. Englar, Advanced aerodynamic devices to improve the performance, economics, handling and safety of heavy vehicles. SAE Technical Report. No. 2001-01-2072, Society of Automotive Engineers (2001)Google Scholar
  7. 7.
    R.P Littlewood, M.A. Passmore, Aerodynamic drag reduction of a simplified squareback vehicle using steady blowing. Exp. Fluids 53 (2), 519–529 (2012)Google Scholar
  8. 8.
    J. Pfeiffer, R. King, Multivariable closed-loop flow control of drag and yaw moment for a 3d bluff body, in Proceedings of the 6th AIAA Flow Control Conference (2012)Google Scholar
  9. 9.
    S. Chaligné, T. Castelain, M. Michard, D. Juvé, Active control of the flow behind a two-dimensional bluff body in ground proximity. C. R. Méc. 341 (3), 289–297 (2013)CrossRefGoogle Scholar
  10. 10.
    H.J. Schmidt, R. Woszidlo, C.N. Nayeri, C.O. Paschereit, Drag reduction on a rectangular bluff body with base flaps and fluidic oscillators. Exp. Fluids 56 (7), 1–16 (2015)CrossRefGoogle Scholar
  11. 11.
    A.R. Oxlade, J.F. Morrison, A. Qubain, G. Rigas, High-frequency forcing of a turbulent axisymmetric wake. J. Fluid Mech. 770, 305–318 (2015)CrossRefGoogle Scholar
  12. 12.
    D. Barros, J. Borée, B.R. Noack, A. Spohn, T. Ruiz, Bluff body drag manipulation using pulsed jets and Coanda effect. J. Fluid Mech. (2016). In printGoogle Scholar
  13. 13.
    J. Östh, B.R. Noack, S. Krajnović, D. Barros, J. Borée, On the need for a nonlinear subscale turbulence term in POD models as exemplified for a high-Reynolds-number flow over an Ahmed body. J. Fluid Mech. 747, 518–544 (2014)MathSciNetCrossRefGoogle Scholar
  14. 14.
    D. Barros, Wake and drag manipulation of a bluff body using fluidic forcing. Ph.D. thesis, École Nationale Supérieure de Mécanique et d‘Aérotechnique (ENSMA), 2015Google Scholar
  15. 15.
    D. Barros, T. Ruiz, J. Borée, B.R. Noack, Control of a three-dimensional blunt body wake using low and high frequency pulsed jets. Int. J. Flow Control 6 (1), 61–74 (2014)CrossRefGoogle Scholar
  16. 16.
    D. Barros, J. Borée, B.R. Noack, A. Spohn, Resonances in the forced turbulent wake past a 3D blunt body. Phys Fluids (1994-present) 28(6), 065104 (2016)Google Scholar
  17. 17.
    C.M. Ho, P. Huerre, Perturbed free shear layers. Ann. Rev. Fluid Mech. 16, 365–422 (1984)CrossRefGoogle Scholar
  18. 18.
    B. Vukasinovic, Z. Rusak, A. Glezer, Dissipative small-scale actuation of a turbulent shear layer. J. Fluid Mech. 656, 51–81 (2010)CrossRefzbMATHGoogle Scholar
  19. 19.
    S.L. Brunton, B.R. Noack, Closed-loop turbulence control: progress and challenges. Appl. Mech. Rev. 67 (5), 050801 (2015)Google Scholar

Copyright information

© Springer International Publishing Switzerland 2017

Authors and Affiliations

  • D. Barros
    • 1
    • 2
    Email author
  • J. Borée
    • 1
  • B. R. Noack
    • 3
    • 4
  • A. Spohn
    • 1
  • T. Ruiz
    • 5
  1. 1.Institut Pprime UPR-3346CNRS – Université de Poitiers – ENSMAChasseneuilFrance
  2. 2.PSA Peugeot CitroënCentre Technique de VélizyVélizy-Villacoublay CedexFrance
  3. 3.LIMSI – CNRS, UPR 3251Campus Universitare dÓrsayOrsay CedexFrance
  4. 4.Institut für StrömungsmechanikTechnische Universität BraunschweigBraunschweigGermany
  5. 5.PSA Peugeot CitroënCentre Technique de VélizyVélizy-Villacoublay CedexFrance

Personalised recommendations