Stall flutter poses great challenges to flight safety. To alleviate this problem, a steady blowing control considering the perturbation and wake-induced vibration at a large angle of attack is developed in this paper, where two blowings are configured on upper and lower tail surfaces to suppress the stall flutter. The stall flutter with one-degree-of-freedom is first evaluated by numerical simulation. The equation of motion for stall flutter is solved by the Newmark-β method. Then, the stall flutter responses for five blowing speeds, i.e., 0, 4, 12, 20, and 28 m/s under the airspeed range of 3–9 m/s, are studied in detail. The stall flutter suppression mechanism can be summarized as follows: a large blowing speed can inject energy into the boundary layer and enhance the high-pressure zone, which delays the flow separation on the suction surface. In this way, the formation of the leading-edge separation vortex is suppressed. Thus, the dynamic stall vortex is weakened and accelerates shedding. In addition, the driving moment is reduced, which leads to a decrement in the stall flutter amplitude. When the blowing speed is 28 m/s (stall flutter amplitude = 0.1357 rad), compared with uncontrolled case (stall flutter amplitude = 0.600 2 rad), the amplitude can decrease by 77.39%, which demonstrates the effectiveness of the proposed steady blowing based active control strategy.

The design of complex aerospace systems is a multidisciplinary design optimization (MDO) problem involving the interaction of multiple disciplines. However, because of the necessity of evaluating expensive black-box simulations, the enormous computational cost of solving MDO problems in aerospace systems has also become a problem in practice. To resolve this, metamodel-based design optimization techniques have been applied to MDO. With these methods, system models can be rapidly predicted using approximate metamodels to improve the optimization efficiency. This paper presents an overall survey of metamodel-based MDO for aerospace systems. From the perspective of aerospace system design, this paper introduces the fundamental methodology and technology of metamodel-based MDO, including aerospace system MDO problem formulation, metamodeling techniques, state-of-the-art metamodel-based multidisciplinary optimization strategies, and expensive black-box constraint-handling mechanisms. Moreover, various aerospace system examples are presented to illustrate the application of metamodel-based MDOs to practical engineering. The conclusions derived from this work are summarized in the final section of the paper. The survey results are expected to serve as guide and reference for designers involved in metamodel-based MDO in the field of aerospace engineering.