Instabilités convectives et absolues dans l'écoulement de Taylor-Couette-Poiseuille excentrique
type: Dataset
description: This work is concerned with the combined effects of eccentricity and pressure-driven axial flow on the linear stability properties of circular Couette flow with a fixed outer cylinder. An example of this flow can be found in oil-well drilling operations. A pseudospectral method is implemented to compute the basic flow, steady and homogeneous in the axial direction, as well as the normal modes of instability. There are four non-dimensional parameters: the radius ratio _ and the eccentricity e for the geometry, the azimuthal and axial Reynolds numbers, Re and Rez, for the dynamics. The first part of the study is devoted to the temporal stability properties. It is found that eccentricity pushes the convective instability threshold towards higher values of Re. The effect of axial advection on the threshold also tends to be stabilising. Eccentricity deforms the modes structure compared to the concentric case. As a result, the mode with the largest temporal growth rate takes the form of 'pseudo-toroidal' Taylor vortices in the absence of axial flow, and 'pseudo-helical' structures with increasing azimuthal order as Rez becomes larger. Results are qualitatively similar for different radius ratios. Agreement with the few available experimental data is good. In a second part, absolute instability is studied by applying the pinch-point criterion to the dispersion relation. Axial flow is found to strongly inhibit absolute instability, the mechanism of which being centrifugal, and the value of Re at the threshold is typically one order of magnitude larger than that of Rez. The effect of eccentricity is more complex: weak stabilisation for low values of e, marked destabilisation for moderate eccentricities and high enough Rez, and finally stabilisation as e is further increased. Unlike temporal instability, the dominant absolutely unstable mode is the 'pseudo-toroidal' Taylor vortex flow over the whole range of parameter space considered.
identifier: NNT: 2013ECDL0046
issued: 2026-05-05T23:06:36.408966
language: en
modified: 2026-05-05T23:06:36.408970
contact point: Organization
  fn: CCSD
keyword: convective-and-absolute-instability
keyword: eccentricity
keyword: ecoulement-de-taylor-couette-poiseuille
keyword: excentricite
keyword: infoeu-reposemanticsdoctoralthesis
keyword: instabilites-convective-et-absolue
keyword: spiotherengineering-sciences-physicsother
keyword: taylor-couette-poiseuille-flow
keyword: theses
landing page: https://theses.hal.science/tel-00962218

Instabilités convectives et absolues dans l'écoulement de Taylor-Couette-Poiseuille excentrique
type: Distribution
format: HTML
issued: 2026-05-05T23:06:36.445669
modified: 2026-05-05T23:06:36.393285
access URL: https://theses.hal.science/tel-00962218

test_moissonnage_selune
type: Agent