Improvement of Aerodynamic Performance of NACA 2412 Airfoil using Active and Passive Control Techniques

Abstract

The study of aerodynamic characteristics plays a crucial role in the design and performance evaluation of various airfoil profiles. In this study, a comprehensive investigation of the modified NACA 2412 airfoil has been carried out, focusing on its aerodynamic characteristics and performance. To improve the aerodynamic characteristics and to delay the stall, active and passive control techniques are introduced. The computational investigation is carried out using commercial software Ansys Fluent. Especially, the Reynolds-Averaged Navier Stokes (RANS) equation is numerically computed employing the K-omega SST turbulence model. The active control is implemented using four microjets, each having diameters of 3 mm, 4 mm, and 5 mm, placed upstream of the flow separation location of the uncontrolled airfoil. The jet exit velocity is maintained the same as the freestream flow velocity. For each case, the tangential orientations of the jets are varied from 2 to 10 degrees with an increment of 2 degrees. Besides, the impact of jet separation distance is also evaluated. On the other hand, the passive control method is introduced by deploying vortex generators (VG) with varying heights of 2 mm, 3 mm, and 4 mm, placed upstream of the separation location. Aerodynamic characteristics, including Lift, Drag, and Stall angle, are measured to assess performance. The study reveals that microjets with a diameter of 5 mm at a 2-degree tangential orientation perform best with a maximum of 11.33% increase in lift coefficient (Cl). For all the three sizes of microjets, the drag coefficients (Cd) are minimum for 2-degree tangential orientation. Besides, the vortex generator of height 2 mm demonstrates superior performance with a maximum of 4% increase in lift coefficient. For both cases, the stall angle of the airfoil is delayed by 28.57%. In addition, except 2mm height of the vortex generator, all other vortex generators lead to an increase in drag coefficient. Importantly, the microjets are proved to be more efficient than the vortex generator in delaying the flow separation thereby reducing the drag and increasing the aerodynamic efficiency of the airfoil.