Recent observations of the transition to turbulence in a pipe

Abstract

We report the results of an experimental investigation of the transition to turbulence of Poiseuille flow in a long pipe. Our findings confirm that the recently established scaling law for the finite amplitude perturbation required to cause transition is O(Re-1). New results are presented concerning the decay of disturbances injected into the flow field at values of Re where the flow is known to be globally stable. Exponential decay and critical behaviour is observed and these are consistent with observations in other shear flows. This new approach has enabled us to uncover a sharp cut off at the lower limit of the stability threshold. © 2006 Springer.