Absolute instabilities in eccentric Taylor–Couette–Poiseuille flow

Absolute instabilities in eccentric Taylor-Couette-Poiseuille flow

The effect of eccentricity on absolute instabilities (AI) in the Taylor–Couette system with pressure-driven axial flow and fixed outer cylinder is investigated. Five modes of instability are considered, characterized by a pseudo-angular order m, with here |m| 6 2. These modes correspond to toroidal (m = 0) and helical structures (m 6= 0) deformed by the eccentricity. Throughout the parameter ra...

Convective and absolute instabilities in counter-rotating spiral Poiseuille flow

We present results of an experimental study on the stability of Taylor–Couette flow in case of counter-rotating cylinders and an imposed axial through flow. We are able to confirm results form recent numerical investigations done by Pinter et al. [24] by measuring the absolute and convective stability boundaries of both propagating Taylor vortices (PTV) and spiral vortices (SPI). Thus our work ...

Absolute and convective instabilities of heated coaxial jet flow

This study investigates the inviscid, linear spatio-temporal stability of heated, compressible and incompressible coaxial jet flows. The influence of the temperature ratio and the velocity ratio between the core jet and the bypass stream on the transition from convectively to absolutely unstable flows is studied numerically. The investigation shows that for coaxial jets absolute instability can...

Absolute instabilities of standing pulses

We analyse instabilities of standing pulses in reaction-diffusion systems that are caused by an absolute instability of the homogeneous background state. Specifically, we investigate the impact of pitchfork, Turing and oscillatory bifurcations of the rest state on the standing pulse. At a pitchfork bifurcation, the standing pulse continues through the bifurcation point where it selects precisel...

Absolute and convective instabilities in a one-dimensional Brusselator flow model