Proper control of unsteady separated flow developments over the lifting surfaces of an aircraft may prove to be an effective method of enhancing aerodynamic lift and producing better aircraft performance. Due to the complexity of unsteady flow separation and subsequent flow developments, experimental exploration and observation are essential in providing a source for comparison and verification with theoretical and computational models. In light of these motivations, a new experimental system that is capable of generating wide of range of unsteady flow histories has been developed and employed to visualize flow developments over an airfoil in accelerated-decelerated motion. The paper presents a description of the experimental system and its use in investigating accelerating flow over a flat plate airfoil at high angles of attack. The experimental results reported in the paper may serve as a useful source to guide and verify computational research efforts that are currently in progress
