Microfluidics and Nanofluidics

, Volume 11, Issue 6, pp 773–780 | Cite as

Microflow-based control of near-wall fluctuations for large viscous drag reduction

  • Jovan Jovanović
  • Bettina Frohnapfel
  • Rubitha Srikantharajah
  • Djordje Jovanović
  • Hermann Lienhart
  • Antonio Delgado
Research Paper

Abstract

The stabilizing effect of microgroove surface morphology on viscous drag reduction was studied experimentally in the inlet region of a plane channel flow. The stabilization is thought to be due to the ability of a microgrooved surface pattern to suppress the velocity fluctuations in the spanwise direction on a restricted portion of the wetted surface, which prevents vorticity development at the wall and consequently across the entire flow field. This smart microflow control strategy, which works successfully only under very particular circumstances, was implemented in a microgroove-modified channel flow in which the front part has a microgrooved surface topology. The results of pressure drop measurements indicate that microgrooved surfaces can effectively stabilize laminar boundary layer development, leading to a significant reduction in the viscous drag. In the rear flat part of the microgroove-modified channel test section, a maximum drag reduction of \({\rm DR\simeq 35\%}\) was measured. This corresponds to an overall drag reduction of \({\rm DR\simeq 16\%}\) at a length Reynolds number of \(Re_x\simeq 10^6. \) The drag reduction effect persisted in a narrow range of flow velocities and for the reported experimental conditions corresponds to microgroove dimensions between 1.5 and 2.5 viscous length-scales.

References

  1. Bushnell DM, Hefner JN, Ash RL (1977) Effect of compliant wall motion on turbulent boundary layers. Phys Fluids 20(Part II):S31–S48CrossRefGoogle Scholar
  2. DIN 24 163 (1985) Normenausschuß Maschinenbau (NAM), Teil 1, 2 und 3. Deutsches Institut für Normung e.V., BerlinGoogle Scholar
  3. Fischer M (1999) Turbulent wall-bounded flows at low Reynolds numbers (in German). PhD thesis, University Erlangen-Nuremberg, ibidem-Verlag, StuttgartGoogle Scholar
  4. Frohnapfel B, Jovanović J, Delgado A (2007) Experimental investigation of turbulent drag reduction by surface-embedded grooves. J Fluid Mech 590:107–116MATHCrossRefGoogle Scholar
  5. Frohnapfel B, Lammers P, Jovanović J, Durst F (2007) Interpretation of the mechanism associated with turbulent drag reduction in terms of anisotropy invariants. J Fluid Mech 577:457–466MATHCrossRefGoogle Scholar
  6. Hinze JO (1975) Turbulence. 2nd edn. McGraw-Hill, New YorkGoogle Scholar
  7. Jovanović J, Frohnapfel B, Škaljić E, Jovanović M (2006) Persistence of the laminar regime in a flat plate boundary layer at very high Reynolds number. J Thermal Sci 10:63–96Google Scholar
  8. Laufer J (1975) New trends in experimental turbulence research. Annu Rev Fluid Mech 7:307–326CrossRefGoogle Scholar
  9. Laufer J (1982) Flow instability and turbulence. In: Zarić Z (ed) Structure of turbulence in heat and mass transfer. Hemisphere, pp 3–5Google Scholar
  10. Lee C, Kim J (2002) Control of the viscous sublayer for drag reduction. Phys Fluids 14:2523–2529CrossRefGoogle Scholar
  11. Moser RD, Kim J, Mansour NN (1999) Direct numerical simulation of turbulent channel flow up to Re τ = 590. Phys Fluids 11:943–945MATHCrossRefGoogle Scholar
  12. Satake S, Kasagi N (1996) Turbulence control with a wall-adjacent thin layer of spanwise damping force. Int J Heat Fluid Flow 17:343–352CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Jovan Jovanović
    • 1
    • 2
  • Bettina Frohnapfel
    • 2
  • Rubitha Srikantharajah
    • 1
  • Djordje Jovanović
    • 1
  • Hermann Lienhart
    • 1
  • Antonio Delgado
    • 1
  1. 1.Institute of Fluid MechanicsFriedrich-Alexander University Erlangen-NurembergErlangenGermany
  2. 2.Center of Smart InterfacesTechnische Universität DarmstadtDarmstadtGermany

Personalised recommendations