École Nationale Supérieure de
Techniques Avancées

Abstract

In the present work, numerical simulations were carried out to analyse the isolated turbulent bands that are characteristic of the transition to turbulence in Poiseuille flow. These bands have only been seen in this particular flow and at moderate Reynolds numbers. So, thanks to the experiments done previously in flows that are intermediate between Couette and Poiseuille flow, we studied the behaviour of the isolated bands when the basic Poiseuille profile is changed. Thus, our numerical simulations have shown that the so-called one-sided regime, where we have these bands in one direction only, exists in a range between the Poiseuille flow and a profile close to the latter, but with some influence of Couette. In addition, velocity measurements were made on the downstream end (or head) of the isolated bands and a linear stability analysis was conducted in the mean flow adjacent to this head which showed that the flow becomes less unstable as the influence of Couette in the base profile increases.