Suction slots on airfoils are a smart aerodynamic feature meant to improve lift and control airflow over the wing surface. These small openings, usually found near the front of the airfoil, create a low-pressure zone that pulls in the surrounding air. This suction effect helps keep the airflow smooth over the wing, maintaining lift even at higher angles. In this intriguing numerical study, suction slot is implemented on a 3D airfoil. Our study receives credit from the reference paper entitled “ Numerical study of blowing and suction slot geometry optimization on NACA 0012 airfoil”.

Figure 1: Suction slot on airfoil leading edge

Simulation Process

Calculations were performed over the NACA 0012 airfoil with a 1 m chord length. The suction slot is located on the suction side near the leading edge. A multizonal structured grid is adopted with a concentration near the suction slot, blade surface, and critical regions. 3746500 cells are meticulously generated. The angle of attack (AoA) is 14°, so there will be wake regions forming behind the airfoil. This encouraged us to adopt a 3-equation turbulence model ( Transition k-kl-omega).

Figure 2: Multizonal structured grid

Post-processing

Based on the contours provided and the solution data, implementing a suction slot on the NACA0012 airfoil at a 14° angle of attack significantly affects the airflow and pressure distribution. The pressure contour shows a distinct low-pressure region (blue area) near the leading edge of the upper surface, indicating the suction slot’s location. This suction effect energizes the boundary layer, which is evident where the streamlines remain attached to the airfoil’s upper surface for a longer distance. The suction slot helps delay flow separation, allowing the airfoil to maintain lift at this relatively high angle of attack. The resulting lift coefficient (Cl) of 0.5308 is considerable for a symmetric airfoil like NACA0012 at this angle. However, the drag coefficient (Cd) of 0.0907 suggests that while the suction slot improves lift, it may introduce additional drag.