Propulsion of an elastic filament in a shear-thinning fluid

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...

Capillarity driven spreading of circular drops of shear-thinning fluid

We investigate the spreading of thin, circular liquid drops of powerlaw rheology. We derive the equation of motion using the thin film approximation, construct source-type similarity solutions and compute the spreading rate, aparent contact angles and height profiles. In contrast with the spreading of newtonian liquids, the contact line paradox does not arise for shear thinning fluids. In this ...

Wave celerity on a shear-thinning fluid film flowing down an incline

Propulsion in a viscoelastic fluid

Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid wi...

Filament attachment dynamics in actin-based propulsion

A. E. Carlsson Department of Physics, Washington University, St. Louis, Mo. 63130 (Dated: February 2, 2008) Abstract Theory and experiment have established that F-actin filaments are strongly attached to the intracellular parasites (such as Listeria) they propel with “comet tails”. We consider the implications of these observations for propulsion. By calculating the motion produced in various m...