The Structure of the Drag Reduced Turbulent Flow over a Backward Facing Step — an experimental study

Part of the Notes on Numerical Fluid Mechanics (NNFM) book series (NONUFM, volume 40)


Aqueous solutions of polyacrylamide (Separan AP45, 50 ppm) or some cationic surfactant additives (mixtures of tetradecyl-trimethyleammoniumbromide with sodium salicylate) exhibit the effect of drag reduction in turbulent pipe flows. From previous investigations it could be concluded that this effect is based on the change of the structure of turbulent motion. The aim of this work is the experimental investigation on the influence of drag reducing additives on the features of turbulence.

The description of turbulent structures leads to a better understanding of the effect of drag reduction and offers deeper insights to turbulence in general. The chosen geometry of a backward facing step supplements investigations of other turbulent flows, e.g. the plane mixing layer (Kwade 1982) or pipe flow (Bewersdorff et al. 1986).


Shear Strain Reynolds Stress Coherent Structure Surfactant Solution Separation Point 
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  1. Antonia, R. A. Conditional sampling in turbulence measurement. Ann. Review of Fluid Mech., 13 (1981) 131–156.ADSCrossRefGoogle Scholar
  2. Bewersdorff, H.-W.; Frings, B.; Lindner, P.; Oberthür, R. C. The conformation of frag reducing micelles from small-angle-neutron-scattering experiments. Rheol. Acta, 25 (1986) pp. 642–646.CrossRefGoogle Scholar
  3. Blackwelder, R. On the role of phase information in conditional sampling. Physics of Fluids, 20 (1977) 232–242.ADSCrossRefGoogle Scholar
  4. Dohmann, J. Anisotrope Turbulenz der Kârmanschen Wirbelstraße - eine phänomenologische Untersuchung. Universität Dortmund, Dissertation 1992.Google Scholar
  5. Hussain, A.K.M.F. Coherent structures and turbulence. J. of Fluid Mech. 173 (1986) 303–356.ADSCrossRefGoogle Scholar
  6. Kaplan, R. E. Conditional sampling techniques. 3rd Sympoium on Turbulence in Liquids (1973) University of Missouri-Rolla.Google Scholar
  7. Kwade, M. Beeinflussung der Turbulenzstruktur in der ebenen Mischungsschicht zweier Ströme durch Polymerzusätze. Rheol. Acta, 21 (1982) pp. 120–149.Google Scholar
  8. Riediger, S. Untersuchung der Turbulenzstruktur in einer ebenen Mischungsschicht und hinter einer Kanalerweiterung bei der Strömung zweier nicht-newtonscher Flüssigkeiten. Universität Dortmund, Dissertation 1989.Google Scholar

Copyright information

© Springer Fachmedien Wiesbaden 1993

Authors and Affiliations

  1. 1.Fachbereich ChemietechnikUniversität DortmundDortmund 50Germany

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