With the increasing use of wormlike micelle solutions as rheological modifiers in many consumer products, the prediction of the behavior of these fluids has grown increasingly important in recent years. In this paper, the flow past a sphere falling at its terminal velocity through a column of a wormlike micelle solution is experimentally studied. The working fluid is an entangled wormlike micel...

An intensionalanswer to a query is a set of characterizations of the set of database values that satisfy the query (the extensional answer). Intensional answers provide users with additional insight into the nature of standard extensional answers. In this paper we describe a method that applies database constraints to generate intensional answers. These intensional answers characterize the exte...

In seeking to understand experiments on low-Reynolds-number mixing and flow transitions in viscoelastic fluids, we simulate the dynamics of the Oldroyd-B model, with a simple background force driving the flow. We find that at small Weissenberg number, flows are "slaved" to the extensional geometry imposed by forcing. For large Weissenberg number, such solutions become unstable and transit to a ...

T This paper reports the mixing performance of an AC electroosmotic micromixer based on the three-dimensional extensional flow generated by a face-to-face, asymmetric pair of planar electrodes. This work represents the first successful use of such an asymmetric electrode pair in an AC electroosmotic micromixer. Due to the highly 3dimentional flow pattern generated by the face-to-face electrode ...

■ Abstract Filament-stretching rheometers are devices for measuring the extensional viscosity of moderately viscous non-Newtonian fluids such as polymer solutions. In these devices, a cylindrical liquid bridge is initially formed between two circular end-plates. The plates are then moved apart in a prescribed manner such that the fluid sample is subjected to a strong extensional deformation. As...

One objective of this study is to assess the influence of the number of dangling arms at each end of the pom-pom molecule on flow characteristics in a 4:1 planar rounded-corner contraction, where varying the number of arms affects the level of entanglement in the system. For these complex flows, we evaluate the major influence of extensional viscosity and Trouton ratio when comparing kinematic-...

Motivated by the aim of modelling the mechanical behaviour of biological gels (such as collagen gels) which have a fibrous microstructure, we consider the extensional flow of a thin two-dimensional film of incompressible, transversely isotropic viscous fluid. Neglecting inertia, and the effects of gravity and surface tension, leading-order equations are derived from a perturbation expansion of ...

Semiflexible polymers subject to hydrodynamic forcing play an important role in cytoskeletal motions in the cell, particularly when filaments guide molecular motors whose motions create flows. Near hyperbolic stagnation points, filaments experience a competition between bending elasticity and tension and are predicted to display suppressed thermal fluctuations in the extensional regime and a bu...

Static and dynamic deformabilities of erythrocytes are important determinants of microcirculatory blood flow. To determine the influence of increased cellular hemoglobin concentration on these properties, we quantitated static and dynamic deformabilities of isolated subpopulations of oxygenated normal and sickle erythrocytes with defined cell densities using micromechanical manipulations of ind...