Numerical and Experimental Investigation of Co-Shedding Vortex Generated by Two Adjacent Circular Cylinders and Its Effect on Air Flow Behaivor around Naca 2412 Airfoil

Abstract

The vortex shedding effect on flow separation around airfoil NACA 2412 was investigated. To control the location of separation point, the turbulent flow was generated. To induce turbulent pattern, flow was disrupted by two adjacent circular cylinders in upstream of  airfoil with 10 mm diameter for each cylinder. An experimental technique based on smoke wind tunnel with different air flow velocities (1.7 m/s and 2.5 m/s) was provided. The conjunction between the effect of the angles of attack and flow visualization around the airfoil NACA 2412 was verification. The angles of attack (0, 5 and 10) degree was used for each air flow velocity. ANSYS program software used to simulate and comparison all the experimental results. The experimental and numerical results showed, when the angle of attack increase, the location of the separation point was shifted toward the airfoil NACA 2412 leading edge. Also, effect of the wake of two cylinders on the location of the separation point was very clear. The vortex induced beyond the cylinders and upstream the airfoil help to prevent separation growth, thereby, the turbulent provided will accelerated the flow around the airfoil geometry and the adverse pressure in that location was decreased. So, the increases in airflow velocity will help the turbulent boundary layer to growth. The growth of turbulent flow boundary layer tends to avoid separation and the flow will reattached. Moreover, the accuracy of results were checked by validation the Kutta-condition experimentally and numerically.

Keywords:  Boundary layer control, airfoil NACA 2412, flow visualization, smoke wind tunnel