Flow Visualisations and PIV Measurements of ZNMF Jet Control of Separated Flow Over NACA0015 Airfoil

This paper presents and describes the results of an experimental study into the control of separated flow over a NACA0015 airfoil over a range of angles of attack at a Reynolds number of 3 × 10⁴. The study was carried out in the LTRAC 500 mm × 500 mm water tunel. The separation control is actuated using a planar zero-net-mass-flow (ZNMF) jet at the leading edge of the airfoil. The ZNMF micro-jet flow is generated using a piston-cylinder arrangement connected to a skotch-yoke mechanisms that is driven by a computer controlled stepper motor. The parameter range for the planar ZNMF jet ranged from non-dimensional frequency of 0.5 to 1.5 and blowing coefficients up to 0.2. A six component force transducer was used to measure the lift and drag force on the airfoil. Planar laser induced fluoresence (PLIF) using Kyton red dye and Nd:YAG laser illumination was used for the flow visualisations. Multigrid cross-correlation digital PIV (MCCDPIV) with pulsed Nd:YAG laser planar illumination was employed with digital imaging of 4008 px × 2672 px to measure instantenous velocity fields.