Convective instability in inhomogeneous media: impulse response in the subcritical cylinder wake
Abstract
We study experimentally the impulse response of a cylinder wake below the critical Reynolds number of the B\'enard-von K\'arm\'an instability. In this subcritical regime, a localized inhomogeneous region of convective instability exists which causes initial perturbations to be transiently amplified. The aim of this work is to quantify the evolution resulting from this convective instability using two-dimensional particle image velocimetry in a hydrodynamic tunnel experiment. The velocity fields allow us to describe the evolution of wave packets in terms of two control parameters: the Reynolds number and the magnitude of the imposed perturbation. The temporal evolution of energy exhibits a transient algebraic growth at short times followed by an exponential decay.
Keywords
Cite
@article{arxiv.1012.1121,
title = {Convective instability in inhomogeneous media: impulse response in the subcritical cylinder wake},
author = {Catherine Marais and Ramiro Godoy-Diana and Dwight Barkley and José Eduardo Wesfreid},
journal= {arXiv preprint arXiv:1012.1121},
year = {2011}
}
Comments
Submitted to Phys. Fluids