Chronology of dynamic stall characteristics through simultaneous PIV and surface pressure measurements

Abstract

Wind tunnel experiments were carried out at low speed aerodynamics lab at IIT Kanpur to investigate dynamic stall characteristics for a flow past an oscillating NACA 0015 airfoil at various reduced frequencies κ. The NACA airfoil model was designed and developed to incorporate simultaneous surface pressure measurement at the mid-span of the airfoil model along the chord and 2D PIV measurements of the flow-field downstream near the Trailing Edge (TE) vicinity of the oscillating airfoil model subjected to the higher reduced frequency κ up to 0.5. The main objective of this work was to critically assess the effect of κ in the unsteady domain from fully develop to partially develop dynamic stall regimes. For a given constant Reynolds number Re of 2 × 105, the instantaneous 2D PIV images were captured for an oscillating airfoil at varied κ. Case studies at κ = 0.01 and 0.10 falling under fully developed dynamic stall regimes are presented and critically assessed to provide qualitative information and flow visualization of the flow field to trace various dynamic stall events which mainly include the formation, growth and shedding of Dynamic Stall Vortex (DSV) from the TE.