Transitional flow of a non-newtonian fluid in a pipe: Experimental evidence of weak turbulence induced by shear thinning behavior

A Esmael (1) , C Nouar (1) , A Lefèvre (1) , N Kabouya (1)

1 LEMTA - Laboratoire d'Energétique et Mécanique Théorique et Appliquée

The present paper is a thorough study of the flow regime where an asymmetry of the mean axial velocity profiles is observed for shear-thinning fluids flow in a pipe [? ]. This study is based on statistical analysis of the axial velocity fluctuations. It is shown that this flow regime exhibits features of a weak turbulence: chaotic in time and regular in space. More precisely: (i) power spectra of axial velocity fluctuations decay following a power law with an exponent very close to −3, (ii) large-scale coherent structures are generated and (iii) there is essentially no intermittency in this flow regime.

Mots clés: numbers: 47.27.Cn; 47.50.-D; 47.27.De; 83.60.Wc

Domaines: Science non linéaire [physics]

A Esmael, C Nouar, A Lefèvre, N Kabouya. Transitional flow of a non-newtonian fluid in a pipe: Experimental evidence of weak turbulence induced by shear thinning behavior. Physics of Fluids, 2010, ⟨10.1063/1.3491511⟩. ⟨hal-03767280⟩