Investigation on the Influence of Vortex Generators on Aerofoil

Abstract

Boundary layer separation is a major cause of concern in the wind turbine and aerospace industries as it adversely affects the performance of aircraft wings and wind turbine blades. The immediate result of flow separation over an aerofoil is a loss in lift and an increase in drag within the stall range, both of which have a negative impact on the overall performance of aerofoils in wind turbines. To overcome this problem, vortex generators (VG), are used for increasing lift force and thus increasing the rotational speed of the blade. They act like small protrusions on wing surfaces which help in energizing the boundary layers thereby delaying the separation and providing a wide range of attached flow over airfoil surface. The present research illustrates the comparative analysis on the various shapes of vortex generators such as rectangular, triangular and gothic by varying the angle of attacks (AOA) from 0–15°. The analysis is performed on the NACA0012 airfoil, which is developed using SOLIDWORKS and analysed on ANSYS 2020 R2 software. The value for lift (Cl) and drag (Cd) coefficients with and without vortex generators are determined using ANSYS Fluent and the contours for velocity and pressure are further mapped using CFD Post. The stall angle is evaluated for each of the vortex generator shapes representing the maximum lift that an aerofoil can achieve. Pressure Coefficients plots are studied to investigate the amount of pressure difference created and its influence on angle of attack at the leading edge of airfoil. An overall comparison is made to determine the best vortex generator shape that delivers maximum lift to the aerofoil. The optimum configuration found for vortex generator is gothic shape which illustrates the maximum lift coefficient value, highest amongst all the three shapes.