ABSTRACT

The aim of the thesis is to control the flow separation of an airfoil by Piezoelectric Actuator on the upper surface. The presence of friction in the flow causes a shear stress at the surface of the body, which in turn contributes to the aerodynamic drag of the body i.e. skin frictions drag. However, friction also causes another phenomenon called flow separation, which in turn creates another source of aerodynamic drag called pressure drag due to separation. From a fluid dynamist’s point of view, the performance of an aircraft is essentially controlled by the development of the boundary layer on its surface and its interaction with the mean flow. This interaction decides the pressure distribution on the airfoil surface, and subsequently the aerodynamic loads on the wing. In order to obtain the highest levels of performance efficiencies for mission varying aircraft, it is necessary to either: (a) alter the boundary layer behavior over the airfoil surface—flow control methods of interest here, and/or (b) change the geometry of the airfoil real time for changing free stream conditions—adaptive wing technology. Alter the boundary layer behavior over the airfoil surface can be changed by Placing Piezoelectric Actuator on the upper surface. The value of the aerodynamic efficiency needs to be maximum i.e. the lift to the drag ratio needs to the maximization. For this case lift should be high and drag should be low, which increases aircraft efficiency. It is shown from the experiment that the flow separation occurs at 8˚ attack angle in regular surface airfoil and at 10˚ attack angle in surface with Actuator at 65%-85% and at 14˚ attack angle in surface with Actuator at 55%-75%.

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