On the moving surface impact on flow field and aerodynamic performance of a thick airfoil

This article involved analyzing the influence of a moving surface on the aerodynamics of an S809 airfoil through numerical simulations. As a means of flow control, a section of the airfoil's surface was substituted with a moving surface. The objective was to attain optimal mechanical efficacy of the airfoil for every angle of attack by examining the impact of the position and speed of the moving surface on the flow characteristics. A computa-tional fluid dynamics (CFD) approach was employed for the flow simulation. For this purpose, an unsteady incompressible finite-volume solver was used by developing an in-house Fortran code. A number of validation studies were conducted to evaluate the numerical solver, and acceptable results were obtained. A fixed Reynolds number of 5000 was used for investigations. The range of angle of attack studied in the present work was be-tween alpha = 10 degrees and alpha = 20 degrees. According to the findings of this study, incorporating a moving surface at an appropriate location and speed could improve the airfoil's overall performance. In further investigations, the best location and speed of the moving surface leading to the highest mechanical performance at each angle of attack were found. The results showed that the moving surface provided the greatest improvement in the lift-to-drag ratio at the angle of attack alpha = 10 degrees by 330% and the least improvement at alpha = 20 degrees by 56%. In addition, by applying the appropriate speed to the moving surface at any angle of attack, the vortex shedding around the airfoil was suppressed.