Flexible balloon actuators for active flow control

A new type of flexible balloon actuator for active flow control is developed. Compared with the existing balloon actuator with a rigid substrate, it possesses total structural flexibility and perfect air-tightness even with internal high pressure gas. Finite element method is used to analyze the mechanical properties of elastic membrane. The maximum deflection of the balloon membrane is calculated to be 1.5 mm. To investigate the control ability of the actuators, numerical simulation is carried out. The results show that the actuators can dramatically alter the flow field within the boundary layer. Flight test shows that the inflated balloon actuators lead to local flow separation. The imbalance of localized pressure on the airfoils induces an extra rolling moment and the rolling angle of the UAV is changed about 30°