BIO-INSPIRED CORRUGATED AIRFOIL AERODYNAMICS UNDER EXTERNAL TURBULENCE AT LOW REYNOLDS NUMBERS

Particle image velocimetry measurements have been undertaken to investigate the aerodynamic performance of bio-inspired corrugated airfoil under the influence of external turbulence. The study is motivated by the gliding flight of dragonflies and its relevance to bio-inspired corrugated wing design for micro air vehicles. The detailed flow-field measurements are undertaken at 6% turbulence intensity for six angles of attack (+/- 5, +/- 10 degrees, and 15 degrees). The low Reynolds number regime from Re = 1200 to 13,200 corresponding to dragonfly flight has been covered in the current study. The aerodynamic performance of the corrugated airfoil is evaluated by obtaining drag and lift coefficients using modified wake survey method and Kutta-Joukowski theorem, respectively. The calculated C-l and C-d are compared with available literature, and it is noted that the performance of corrugated profile airfoil degrades significantly under the influence of external turbulence. The temporal wake obtained from the mean velocity fields is also presented for better visualization of flow dynamics. The findings of the study indicate that the performance of corrugated airfoil under external turbulence is strongly influenced by angle of attack at lower Re.