How do different types of jets control dynamic stall?

In the history of aircraft development, maneuverability has always been an important consideration in the design concept of aircraft. The requirements for aerodynamic characteristics are reflected in high lift-to-drag ratio, high lift coefficient, torque stability and so on. The occurrence of dynamic stall will lead to a sharp drop in lift and a rapid rise in drag, resulting in torque oscillation, which seriously restricts the improvement of aircraft performance, and even leads to aircraft crash in severe cases. The traditional passive flow control cannot cope with the real-time and changeable flow field environment during dynamic stall, and the emergence of jet control provides a new way to solve the problem of dynamic stall. Although the research of single jet technology has been relatively sufficient, there are few comparative studies on steady jet and Synthetic Jet (SJ), and there is also a lack of related research on Dual Synthetic Jets（DSJ）. Therefore, it is imperative to fill this research gap.

Recently, a team of aerodynamic scientists led by Zhenbing LUO of the National University of Defense Technology conducted research in this area. This work not only reports the control mechanism of different jet control dynamic stall phenomenon, but also finds the characteristics of DSJ quasi-steady characteristics, which means that DSJ combines the stability of steady jets and the efficiency of pulsed jets, so that it maintains the advantage of better control effect under the same momentum coefficient of pulsed jets while maintaining aerodynamic stability. This feature is unique in the field of jet control.

Their work, published in the Chinese Journal of Aeronautics (Vol. 38, Issue 6, 2025), demonstrates the efficient performance of a new flow control method to control flow separation.

In this paper, they study the effect of different jet techniques to control dynamic stall by simulation. In the process of analysis, the coanda effect and quasi-steady characteristics of DSJ were found. Through quasi-steady characteristics, the control of DSJ will not lead to large fluctuations in real-time aerodynamics. Zhenbing LUO, a professor at the School of Aerospace Sciences, National University of Defense Technology, is a senior expert in the field of aerodynamics.

“DSJ unexpectedly plays a decisive role in controlling dynamic stall. This unique working mechanism makes it maintain the advantage of better control effect under the same momentum coefficient of pulse jet, while maintaining the aerodynamic stability, showing unique advantages in aerodynamic control. This characteristic has not been reported. For a new feature, it is necessary to further explore it.” LUO said.

By analyzing the formation mechanism of different jets, it can be found that the two cavities of the DSJ have opposite phases. At any time of operation, there is always a jet orifice that exerts an effect on the flow field. Like the steady jet, it can continuously control the flow field. Therefore, it avoids the problem that all pulsed jets need energy reserve gap period, so it has quasi-steady characteristics.

The performance of DSJ with two opposite types of jet properties is unique. In the control effect, DSJ also shows the optimal control effect. Both flow field control, aerodynamic control and stability control show better control ability than steady jet and SJ. From the simulation results, DSJ is an excellent jet control technology.

Other contributors include Jianyu GONG, Wenqiang PENG, Xiong DENG, Yan ZHOU, Jianyuan ZHANG, Zhijie ZHAO, all from National University of Defense Technology.

Original Source

Jianyu GONG, Wenqiang PENG, Zhenbing LUO, Xiong DENG, Yan ZHOU, Jianyuan ZHANG,

Zhijie ZHAO. Comparison of aerodynamic characteristics of wing dynamic stall under three typical jets control [J]. Chinese Journal of Aeronautics, 2025, 38(6): 103284. https://doi.org/10.1016/j.cja.2024.10.016.

About Chinese Journal of Aeronautics 

Chinese Journal of Aeronautics (CJA) is an open access, peer-reviewed international journal covering all aspects of aerospace engineering, monthly published by Elsevier. The Journal reports the scientific and technological achievements and frontiers in aeronautic engineering and astronautic engineering, in both theory and practice. CJA is indexed in SCI (IF = 5.3, top 4/52, Q1), EI, IAA, AJ, CSA, Scopus.