Artificial Turbulent Bursts

To gain understanding of the physical and structural events in the turbulent bursting process, an effort to generate artificial bursts in a turbulent boundary layer was made. Turbulent bursts, which are both random in time and in space, and cause a large portion of drag of a turbulent boundary layer. Control of the bursts could yield a decrease in skin friction and hence drag. Data were taken in a turbulent boundary layer developed over a flat plate in a low-speed wind tunnel with an array of eight hot-wire probes. The turbulent burst like events were created by pitching a rectangular shaped piezoelectric bimorph actuator out into the flow. The actuator effect is proposed which models the production of counter-rotating vortices in a rectangular vortex filament configuration. The results are compared with naturally occurring bursts and data from previous studies. Knowing more about the turbulent bursting process gives us more opportunities to control the turbulent bursts and therefore reduce drag over airfoils