title: Resonant enhancement of turbulent energy dissipation.
abstract: We periodically modulate a turbulent wind-tunnel flow with an active grid. We find a resonant enhancement of the mean turbulent dissipation rate at a modulation frequency which equals the large-eddy turnover rate. Thus, we find the best frequency to inject energy into a turbulent flow. The resonant response is characterized by the emergence of vortical structures in the flow and depends on the spatial mode of the stirring grid.
authors.affiliation: Physics Department, Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Hakki Ergun
authors.initials: HE
authors.lastname: Cekli
authors.forename: Carl
authors.initials: C
authors.lastname: Tipton
authors.forename: Willem
authors.initials: W
authors.lastname: van de Water