Aerodynamic characteristics and flow topology of tapered symmetrical airfoil equipped with Clark-Y shaped vortex generators

The aerodynamic characteristics and surface flow topology of tapered swept-back National Advisory Committee for Aeronautics 0020 airfoil equipped with Clark-Y shaped vortex generators (CsVGs) are researched. The force and surface oil flow visualization for the tapered swept-back wing having a swept angle of 25° and a taper ratio of 0.4 is performed at a Reynolds number (Re) of 1.2×105 via CsVGs at x/c = 0.2, 0.3, 0.4, and 0.5. The airfoil equipped with CsVGs at x/c = 0.2 [T2 at an angle of attack (AoA) of 13°] showed a 15.53% improvement in the maximum CL and a delaying stall by 2° comparison with the baseline [at AoA of 11°]. According to oil flow visualization, the T2 model enhanced the post stall characteristics via CsVGs by increasing the attached flow region from the root to the tip as compared to the baseline. While the straight laminar separation bubble (LSB) for the baseline was observed, a wavy LSB for T2 occurred due to the interaction of LSB with CsVGs located at 0.2c. Primary attach flow regions on the downstream of each CsVG, attached flow regions on the downstream of CsVG pairs, and interaction line due to the interaction of primary and attached flow region were identified via oil flow visualization.