Flow control for low-reynolds number airfoil performance enhancement using response surface methodology

Low Reynolds number flows are characterized by boundary layer separation due to the effect of viscous forces. The separated flow may reattach through the exchange between the molecules resulting in Laminar Separation Bubble LSB. LSB, known for its detrimental effect on the performance is sensitive to the airfoil geometry. The current paper describes the use of trip boundary on the suction surface of SD7003 airfoil as flow control technique to enhance the airfoil performance at Re = 6 X 104 and α = 4deg using numerical analysis. Due to the complexity of finding the trip size and location, Response Surface Methodology RSM is used to obtain the optimum combinations between the height, width and the position of the turbulator. Thus, the design variables are the height [0.2mm,0.6mm], width [140mm, 200mm] and the position of the trip away from the leading edge [10%c, 25%c]. Using the Desirability approach with Nelder-Mead simplex algorithm, the trip location is found to be effective downstream the separation location of the untripped airfoil. At the optimum design parameters, the length of LSB has decreased by 2.32% and the airfoil performance increased by 6%.