Abstract:
Active flow control on a free-wing at low Reynolds number has been investigated experimentally by using beveled-slit-synthetic-jet (BSSJ). Synchronous measurement of visual pressure transducer system and PIV (Particle Image Velocimetry) has been used to investigate the mechanism of free-wing during the transients of AOA (angle of attack) following the onset of BSSJ. Results reveal that the maximal balanced AOA is only 5° in low Reynolds number (
Re=1.24×10
5), whereas it is 16.8° with BSSJ control. Due to the influence of flow separation at upper surface at balanced AOA up to 5°, the efficiency of control surface of free-wing is reduced remarkably. Energy injection in the boundary layer prompts the attachment of separation flow at upper surface and improves the efficiency of control surface. Upward force moment leads free-wing to increase the AOA and reaches to a new balanced AOA. Trimming at high balanced AOA has an important significance, with the control of BSSJ, upon SLOT (Short Take Off and Landing).