Aerodynamic characteristics of unsymmetrical aerofoil at various turbulence intensities

A series of wind tunnel tests were performed to investigate the effect of turbulent inflows on the aerodynamic characteristics of the unsymmetrical airfoil at various turbulence intensities and Reynolds number. To assess the aerodynamic characteristics, surface pressure measurements were made over the unsymmetrical airfoil surface by using a simultaneous pressure scanner MPS4264 of Scanivalve make. Self-generated passive grids made of parallel arrays of round bars were placed at four different locations to generate various Turbulence Intensities (TI) in the wind tunnel. The location of the passive grid has been normalized in terms of considering the distance between the entry of the test section and the leading edge of the model. Based on the wind tunnel results, by comparing the baseline without grid low turbulence case TI = 0.51% with other turbulence generated cases like TI = 4.68%, 4.73%, 6.04% and 8.46% at different Reynolds number, it is found that the coefficient of lift increases with the increase in the turbulence intensity. Results also reveal that the flow featuring turbulence can effectively delay the stall characteristics of an airfoil by attaching the flow over the airfoil for an extended region. Additionally, attempts were made to understand the influence of turbulence on the aerodynamic hysteresis.