High-Reynolds-number turbulence in complex fluids

¹ Laboratoire de Physique Statistique, Ecole Normale Supérieure - 24 rue Lhomond, 75005 Paris, France, EU
² Van der Waals-Zeeman Institute, University of Amsterdam - Science Park 904, 1098 XH Amsterdam, The Netherlands, EU
³ U. Bordeaux 1, Laboratoire Ondes et Matière d'Aquitaine, UMR 5798 CNRS - 351 cours de la Libération 33405 Talence, France, EU

Received: 17 September 2012
Accepted: 9 January 2013

Abstract

We here examine the structure of turbulence in the case of a complex fluid made up of water and surfactants. This fluid has the particular property of shear thickening when driven at shear rates above a certain threshold. Through a study of the spectral properties and the structure function scalings, important differences arise with respect to the reference case, i.e., water. The surfactant solution shows strong intermittency at small scales. The large scales are, on the other hand, free of intermittency. While this transition is observed in the structure function scalings, no sign of this transition is seen in the power spectrum of velocity fluctuations which shows a single scaling range. The strongly intermittent small-scale region, despite the scaling of the power spectrum, exhibits properties reminiscent of the near-dissipative range.