We have implemented the log-conformation method for two-dimensional viscoelastic flow in COMSOL, a commercial high-level finite element package. The code is verified for an Oldroyd-B fluid flowing past a confined cylinder. We are also able to describe the well-known bistability of the viscoelastic flow in a crossslot geometry for a FENE-CR fluid, and we describe the changes required for perform...

A mathematical approximation technique has been used for the analysis of pressure-volume and decay curves to see which of two concepts of the mechanical properties of the coats of the eye is the more valid. One concept—that the outer coats are nonlinear elastic—stems from the early work of Friedenwald* and is currently in use. The other concept—that the outer coats are nonlinear viscoelastic—st...

We present a generalized nonlinear theory for large-amplitude electrostatic (ES) ion shocks in collisional quantum plasmas composed of mildly coupled degenerate electron fluid of arbitrary degeneracy and nondegenerate strongly correlated ion fluid with arbitrary atomic number. For our purposes, we use the inertialess electron momentum equation including the electrostatic force, pressure gradien...

In active microrheology, a strong external force is applied to a colloidal probe immersed in a complex fluid, so that among other quantities the nonlinear force-velocity relation can be measured. It provides information on the local viscoelastic properties of the complex fluid or soft solid. Generally, in dense fluids, the probe’s friction coefficient decreases strongly with increasing force [1...

The thermal instability of a rotating Rivlin-Ericksen viscoelastic fluid in the presence of uniform vertical magnetic field is considered. For the case of stationary convection, Rivlin-Ericksen viscoelastic fluid behaves like a Newtonian fluid. It is found that rotation has a stabilizing effect, whereas the magnetic field has both stabilizing and destabilizing effects. Graphs have been plotted ...

The influence of fluid–fluid interfacial properties on the dynamics viscoelastic thin liquid films bounded above by liquid–liquid interface and below a horizontal solid plate is studied in this work. present study allows for integration both chemical physical film within long wave approximation evolution equation films. effects contact angle, slippage exposure time are verified. We demonstrate ...

Micropipette aspiration (MA) technique has been widely used to measure the viscoelastic properties of different cell types. Cells experience nonlinear large deformations during the aspiration procedure. Neo-Hookean viscohyperelastic (NHVH) incompressible and compressible models were used to simulate the creep behavior of cells in MA, particularly accounting for the effect of compressibility, bu...

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Polymer solutions and melts are viscoelastic; they exhibit fluidlike behavior in steady shear, but the initial response to an imposed deformation involves a material-dependent transient that may be many orders of magnitude longer than time scales associated with instrument inertia. Intrinsic material time scales can be identified with the dynamics of the macro­ molecular chains. Shaping process...

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...