instability of viscoelastic fluids in nearly parallel flows: a pseudo-spectral analysis

Potential flows of viscous and viscoelastic fluids

Potential flows of incompressible fluids admit a pressure (Bernoulli) equation when the divergence of the stress is a gradient as in inviscid fluids, viscous fluids, linear viscoelastic fluids and second-order fluids. We show that in potential flow without boundary layers the equation balancing drag and acceleration is the same for all these fluids, independent of the viscosity or any viscoelas...

A Fast Immersed Boundary Fourier Pseudo-spectral Method for Simulation of the Incompressible Flows

Abstract   The present paper is devoted to implementation of the immersed boundary technique into the Fourier pseudo-spectral solution of the vorticity-velocity formulation of the two-dimensional incompressible Navier-Stokes equations. The immersed boundary conditions are implemented via direct modification of the convection and diffusion terms, and therefore, in contrast to some other similar ...

Parallel Pseudo-spectral Method for Two-phase Flows

INTRODUCTION Flows involving two phases can be found in many industrial applications. Models that can accurately predict the behaviour of these ows in complex physical situations such as turbulent ow with rotation, and unsteady turbulent two-phase ows, are lacking. Numerical simulation of the detailed behaviour of the drops or bubbles in a complex and unsteady turbulent ow can provide a fundame...

Parallel Computation of Two-Dimensional Rotational Flows of Viscoelastic Fluids in Cylindrical Vessels

The numerical simulation of two-dimensional incompressible complex flows of viscoelastic fluids is presented. The context is one, relevant to the food industry, of mixing within a cylindrical vessel, where stirrers are located on the lid of the vessel. Here, the motion is considered as driven by the rotation of the outer vessel wall, with various stirrer locations. With a single stirrer, both a...

Title Chaos analysis of viscoelastic chaotic flows of polymeric fluids in a micro-channel

Asymmetric flows of viscoelastic fluids in symmetric planar expansion geometries

The flow of viscoelastic liquids with constant shear viscosity through symmetric sudden expansions is studied by numerical means. The geometry considered is planar and the constitutive model follows the modified FENE-CR equation, valid for relative dilute solutions of polymeric fluids. For Newtonian liquids in a 1:3 expansion we predict the result that the flow becomes asymmetric for a Reynolds...