Convective instabilities in a backward-facing step flow: global forced perturbations

O. Marquet; D. Sipp

doi:10.1051/eucass/201203451

All issues

Volume 3 (2012)

10.1051/eucass/201203451

Abstract

Open Access

Issue		Volume 3, 2012 Progress in Flight Physics


Page(s)		451 - 460
Section		Chapter Six. Flow Control
DOI		https://doi.org/10.1051/eucass/201203451
Published online		29 January 2013

Progress in Flight Physics 3 (2012) 451-460

Convective instabilities in a backward-facing step flow: global forced perturbations

O. Marquet¹^,2 and D. Sipp¹

¹ DAFE, ONERA Meudon, France
² LadHyx, CNRS-Ecole Polytechnique Palaiseau, France

Abstract

The two-dimensional (2D) stability of a backward-facing step fiow is investigated at the low Reynolds number Re = 500. Optimal energy growth of linear perturbations sustained by harmonic forcing is computed for several frequencies. The maximum sustained energy growth is of order 10⁵ at frequency f_S ∼ 0.08 and is related to the excitation of Kelvin-Helmholtz instability in the shear layer of the separated fiow. Stability results are compared to a direct numerical simulation (DNS) forced by a random signal.