Drag reduction of a generic transport vehicle model using a fluidic oscillator

Abstract

Base blowing is performed using a sweeping jet actuator centrally located at the base of a square-back Ahmed body. Drag reduction along with a significant effect in terms of wake RSB mode suppression is reported for such fluid injection. All three scales of fluidic actuation exhibit similar wake bistability suppression characteristics. RSB mode suppression is also corroborated through independent force measurements. For all scales of actuators, the optimal blowing coefficient Cqopt is found to scale with bleed-to-base area ratio as (Sj/S)3/4, whereas the blowing coefficient corresponding to the minimum magnitude of wake asymmetry scales as Cqopt(Sj/S)5/12. The small-scale actuator also presents a more energy-efficient base blowing in terms of the amount of drag reduction achieved per energy consumed.

Keywords

• Bluff body wake
• Wake asymmetry
• Flow control
• Fluidic oscillator
• Drag reduction