Linear instability of viscoelastic pipe flow

On the instability of pipe Poiseuille flow

Stability of the flow of incompressible viscous fluid in a circular pipe is studied numerically. A perturbation consisting of finite-amplitude two-dimensional and infinitesimal three-dimensional parts is imposed on the basic flow. The temporal evolution of the perturbation is analyzed by direct numerical calculation of the Navier–Stokes equations. The two-dimensional disturbances are independen...

Viscoelastic potential flow analysis of capillary instability

Analysis of the linear theory of capillary instability of threads of Maxwell fluids of diameter D is carried out for the unapproximated normal mode solution and for a solution based on viscoelastic potential flow. The analysis here extends the analysis of viscous potential flow [Int. J. Multiphase Flow 28 (2002) 1459] to viscoelastic fluids of Maxwell type. The analysis is framed in dimensionle...

Streak breakdown instability in pipe Poiseuille flow

This work is devoted to the study of the stability of Hagen–Poiseuille flow or pipe flow. The analysis is focused on the streak breakdown process by which two-dimensional streamwise-independent finite amplitude perturbations transiently modulate the basic flow leading to a profile that contains saddle points and is linearly unstable with respect to very small streamwise-dependent perturbations....

Faraday instability in a linear viscoelastic fluid

– The onset of surface waves in a vibrated layer of a viscoelastic fluid is investigated theoretically. For vibration frequencies close to the inverse relaxation time of the non-Newtonian fluid, surface waves respond harmonically instead of being subharmonic as is usually the case in Newtonian fluids. This prediction has been made on the basis of the Maxwell model for viscoelastic fluids, but t...

Modeling of viscoelastic turbulent flow in channel and pipe