Experimental study on the effect of boundary layer control on the aerodynamics characteristics of NACA 0021 Aerofoil

Take-off and landing are the critical phases of an aircraft flight where there is a high demand of lift force at the lowest stalling speed of aircraft. Use of different techniques to increase the lift force during these phases of flight is one of the prime objectives in the design of an aircraft wing. Delaying and eliminating flow separation using boundary layer control (BLC) techniques will improve the aerodynamic characteristics of a wing. This work presents an experimental study on the effect of BLC on the aerodynamic characteristics of NACA 0021 aerofoil. Both the techniques of blowing and suction has been considered in this study. Model was built using composites and tested in a subsonic wind tunnel integrated with a compressor/vacuum pump setting for to control the boundary layer on the aerofoil. Firstly, the model with 20 pressure tappings was tested without BLC and the point of flow separation was noted. Later, the suction and blowing holes were made suitably in the model and equipped with a compressor/vacuum pump to control the boundary layer and study the effects of it on the performance of NACA 0021 aerofoil. As expected, the BLC by both the techniques show improvement in the maximum lift coefficient