Classically, a compressible, isothermal, viscous fluid is regarded as a mathematical continuum and its motion is governed by the linearized continuity, Navier-Stokes, and state equations. Unfortunately, solutions of this system are of a diffusive nature and hence do not satisfy causality. However, in the case of a half-space of fluid set to motion by a harmonically vibrating plate the classical...

Abstract We present numerical techniques for calculating instability thresholds in a model thermal convection complex viscoelastic fluid of Kelvin–Voigt type. The theory presented is valid various orders an exponential fading memory term, and the strategy obtaining neutral curves discussed general case. Specific results are order zero, also known as Navier–Stokes–Voigt fluid, fluids 1 2. For la...

in this paper, we present an analytical method for solving a well-posed boundary value problem of mathematical physics governing the vibration characteristics of an internal flow propelled fluid-structure interaction where the pipeline segment is idealized as an elastic hollow beam conveying an incompressible fluid on a viscoelastic foundation. the effect of coriolis and damping forces on the o...

Abstract The effective thermal expansion coefficient β∗ of a binary viscoelastic composite is shown to be frequency dependent even if the thermal expansion coefficients βA and βB of both constituents are themselves frequency independent. Exact calculations for binary viscoelastic systems show that β∗ is related to constituent values βA, βB , volume fractions, and bulk moduli KA, KB , as well as...

We study theoretically the viscoelastic properties of sheared binary fluids that have strong dynamical asymmetry between the two components. The dynamical asymmetry arises due to asymmetry between the viscoelastic stresses, particularly the bulk stress. Our calculations are based on the two-fluid model that incorporates the asymmetric stress distribution. We simulate the phase separation proces...

We study a defect correction method for the approximation of viscoelastic fluid flow. In the defect step, the constitutive equation is computed with an artificially reduced Weissenberg parameter for stability, and the resulting residual is corrected in the correction step. We prove the convergence of the defect correction method and derive an error estimate for the Oseen-viscoelastic model prob...

We study a nonlinear, unsteady, moving boundary, fluid-structure interaction (FSI) problem arising in modeling blood flow through elastic and viscoelastic arteries. The fluid flow, which is driven by the time-dependent pressure data, is governed by 2D incompressible Navier-Stokes equations, while the elastodynamics of the cylindrical wall is modeled by the 1D cylindrical Koiter shell model. Two...

Many small organisms self-propel in viscous fluids using travelling wave-like deformations of their bodies or appendages. Examples include small nematodes moving through soil using whole-body undulations or spermatozoa swimming through mucus using flagellar waves. When self-propulsion occurs in a non-Newtonian fluid, one fundamental question is whether locomotion will occur faster or slower tha...

The study aims at quantifying the effect of fluid elasticity on frictional pressure drop for the flow of viscoelastic fluid through a helical coil. Aqueous solutions of polyacrylamide (PAA) in the concentration range 0.25 %–0.5 % (wt/vol.) were used as test fluids. The fluids were characterized using dynamic rheometer under rotational and oscillatory modes. The rheological study depicts that th...

The simulation of highly viscoelastic fluid flow problems is still plagued with the so-called high Weissenberg problem (HWP). The Weissenberg number We is the ratio of the magnitude of the elastic forces to that of the viscous forces. Most (if not all) numerical methods lose convergence i.e. fail to generate any result and/or fail to generate convergent solutions with respect to mesh size, at s...