Resonant enhancement of turbulent energy dissipation.
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.
Cekli
Hakki Ergun
HE
Physics Department, Eindhoven University of Technology, Postbus 513, 5600 MB Eindhoven, The Netherlands.
Tipton
Carl
C
van de Water
Willem
W