Investigations of Flow Phenomena Over a Flat Plate and NACA0012 Airfoil at High Angles of Attack

Abstract

In the present study, the flow and aerodynamic features of a sharp trailing edged flat plate airfoil are systematically compared with NACA0012 airfoil. The studies are conducted for three different Reynolds numbers 1.89 × 10⁵, 2.83 × 10⁵ and 3.78 × 10⁵ and angles of attack 20°, 25° and 30°. The present study shows that the occurrence of vortex shedding phenomena for the flat plate is substantially different from NACA0012 airfoil. Further, the re-attachment location of the shed vortices is closer to the trailing edge for the flat plate, whereas for NACA0012 airfoil it occurs at a certain distance upstream of the trailing edge. The NACA0012 airfoil generates higher lift coefficients at a higher Reynolds numbers of 2.83 × 10⁵ and 3.78 × 10⁵, whereas for the flat plate it occurs at a lower Reynolds number of 1.89 × 10⁵. The spectra of lift coefficient reveal that the amplitude of the primary shedding frequency dominates for the flat plate and NACA0012 airfoil at lower and higher Reynolds numbers of 1.89 × 10⁵ and 3.78 × 10⁵, respectively, while it becomes almost same for an intermediate Reynolds number of 2.83 × 10⁵. The present study reveals that the drag coefficient at high Reynolds number (3.78 × 10⁵) is directly proportional to the initial merging point of the two shed vortices for both the flat plate and NACA0012 airfoil.