Numerical Analysis of NACA Aerofoil Using Synthetic Jet

Abstract

Usually at high angle of attack, aerofoil stalls due to flow separation on suction surface of aerofoil. To delay the flow separation, pulsating jet arrangement, known as Synthetic jet is used in aerofoil. It is produced by periodic suction and ejection of fluid from an orifice. This condition can be achieved by inducing movement to diaphragm or by giving a zero mass flux sinusoidal boundary condition to the jet. This allows the reattachment of boundary layer which improves the lift and drag performance and angle at also delays stalling angle. In present study, CFD analysis on NACA0015 aerofoil is performed for different angles of attack and the Co-efficients of Drag (Cd) and Lift (C1) are validated with the experimental results of Gilarranz et al. [1]. The flow is simulated by solving Unsteady RANS coupled with k-ε realizable turbulence model with enhanced wall treatment. Synthetic jet is placed in NACA0015 airfoil at 12% of the chord length with width as 0.53% of chord and is studied for a Reynolds number Re = 8.96 × 105 and for angle of attack from 12 to 20 degrees [2]. The jet is almost tangential to the wall at an angle, αjet = 10° and chord length is considered as 0.375m for the study. Further, parametric analyses are conducted on NACA 0015 aerofoil to investigate effect of parameters (frequency, jet angle, jet velocity). It is observed that aerofoil’s performance is improved significantly for jet angle (30°–40°), jet frequency (100 Hz) and non dimensional jet velocity (1.8–2.0). A maximum increase of approximately 26% in Lift was observed at AOA 20°.