Passive Flow Control around NACA 0018 Airfoil Using Riblet at Low Reynolds Number

Abstract

In this study, aerodynamic capabilities of NACA 0018 airfoil is numerically investigated by installing riblet on the suction side of airfoil. Numerical results were obtained by ANSYS Fluent using k-kl-kw transition model at Reynolds number of Re=100 000. Three different riblet airfoil configuration was performed at six different angles of attack (α=8°, 10°, 13°, 15°, 17° and 19°) and these results compared with the clean model. For M1 model the riblet was located at chord wise section of x/c=0.3 while it installed at x/c=0.7 for M2 model. For M3 model two riblets were used and they were located at both x/c=0.3 and x/c=0.7. Obtained numerical result show that the use of riblet remarkably affects the flow characteristics of airfoil. At α=8° the CL/CD value of M1 model is increased by 4.5% when compared to clean model. It is indicated that angle of attack at α=10o, lift coefficient is increased for all models with compared to clean model. Stall angle is delayed from α=13° to α=15° at M1 and M3 with compared to clean model and lift coefficient is increased about 37% because of the restriction of the laminar separation bubble and trailing edge separation.In this study, aerodynamic capabilities of NACA 0018 airfoil is numerically investigated by installing riblet on the suction side of airfoil. Numerical results were obtained by ANSYS Fluent using k-kl-kw transition model at Reynolds number of Re=100 000. Three different riblet airfoil configuration was performed at six different angles of attack (α=8°, 10°, 13°, 15°, 17° and 19°) and these results compared with the clean model. For M1 model the riblet was located at chord wise section of x/c=0.3 while it installed at x/c=0.7 for M2 model. For M3 model two riblets were used and they were located at both x/c=0.3 and x/c=0.7. Obtained numerical result show that the use of riblet remarkably affects the flow characteristics of airfoil. At α=8° the CL/CD value of M1 model is increased by 4.5% when compared to clean model. It is indicated that angle of attack at α=10o, lift coefficient is increased for all models with compared to clean model. Stall angle is delayed from α=13° to α=15° at M1 and M3 with compared to clean model and lift coefficient is increased about 37% because of the restriction of the laminar separation bubble and trailing edge separation.