Self-sustaining process through streak generation in a flat-plate boundary layer.
The existence of a self-sustaining process between streamwise vortices and streaks has been suggested at moderate Reynolds numbers. Such a mechanism has never been demonstrated experimentally. Using small cylinders as vortex generators to create streamwise counterrotating vortices, we show, through the characterization of the spatial transient growth of the energy of the longitudinal and spanwise velocity perturbations, that such a mechanism exists above a given Reynolds number. From instantaneous particle image velocimetry fields in a horizontal plane, we show that the self-sustaining process can also be associated with the longitudinal destabilization of streamwise streaks.
Duriez
Thomas
T
Laboratoire PMMH, UMR7636 CNRS/ESPCI/Paris 6/Paris 7, Ecole Supérieure de Physique et de Chimie Industrielles, 10 rue Vauquelin, 75005 Paris, France.
Aider
Jean-Luc
JL
Wesfreid
José Eduardo
JE