The effect of the riblets on flow control of NACA0018 at low reynolds number

In recent years, numerical and experimental aerodynamic studies have been focused on low Reynolds number flows in order to control turbulence transition and laminar separation bubble of unmanned aerial vehicles and wind turbines. In this thesis, numerical analysis was performed to control of flow over NACA 0018 airfoil using riblet surface at Reynolds number of Re=1x105 in order to increase aerodynamics coefficients such as lift and lift to drag ratio. The riblets were located on the suction surface of airfoil. The main parameters were selected as the height of riblet, location, gap ratio between riblets, the size of riblet region and angle of attack. The numerical analyzes were carried out using k-kL-ω transition model. The obtained results indicate that the height of riblet remarkably affects the formation of laminar separation bubble and increase the lift coefficient in comparison with clean airfoil.