Amplification of localized body forces in channel flows of viscoelastic fluids

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...

Worst-case amplification of disturbances in inertialess flows of viscoelastic fluids

Amplification of deterministic disturbances in inertialess channel flows of viscoelastic fluids is studied by analyzing the frequency responses from spatio-temporal body forces to the velocity fluctuations. In strongly elastic flows, we show that velocity fluctuations can exhibit significant amplification even in the absence of inertia. Our analysis demonstrates that streamwise-constant disturb...

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...

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

in the present work, the effect of fluid’s elasticity was investigated on the hydrodynamic instability of blasius flow. to determine the critical reynolds number as a function of the elasticity number, a two-dimensional linear temporal stability analysis was invoked. the viscoelastic fluid is assumed to obey the walters’ b fluid model for which base flow velocity profiles were fortunately avail...