Reverse flow and vortex breakdown in a shear-thinning fluid

Vortex shedding in cylinder flow of shear-thinning fluids I. Identification and demarcation of flow regimes

An experimental study on the flow of non-Newtonian fluids around a cylinder was undertaken to identify and delimit the various shedding flow regimes as a function of adequate non-dimensional numbers. The measurements of vortex shedding frequency and formation length (lf ) were carried out by laser-Doppler anemometry in Newtonian fluids and in aqueous polymer solutions of CMC and tylose. These w...

Mixing in a vortex breakdown flow

Degassing cascades in a shear-thinning viscoelastic fluid.

We report the experimental study of the degassing dynamics through a thin layer of shear-thinning viscoelastic fluid when a constant air flow is imposed at its bottom. The fluid is an aqueous solution of cetyltrimethylammonium bromide (CTAB) and sodium salicylate (NaSal). Over a large range of parameters, the air is periodically released through a series of successive bubbles, hereafter named c...

Gravity-Driven Flow of a Shear-Thinning Power– Law Fluid over a Permeable Plane

The flow of a thin layer of power-law fluid on a porous inclined plane is considered. The unsteady equations of motion are depth-integrated according to the von Karman momentum integral method. The variation of the velocity distribution with the depth is accounted for, and it is furthermore assumed that the flow through the porous medium is governed by the modified Darcy’s law. The stability co...

Turbulent pipe flow of shear-thinning fluids

Direct numerical simulation of the weakly turbulent flow of non-Newtonian fluids is undertaken for two different generalised Newtonian rheology models using a spectral element-Fourier method. Results for a power law (shear-thinning) rheology agree well with experimentally determined logarithmic layer correlations and with other previously published experimental work. As the flow index becomes s...