A novel fluidic thrust-vectoring (FTV) control method based on dual synthetic jets actuator (DSJA) is proposed and evaluated. Numerical simulations are governed by the compressible Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations. According to the results, DSJA is capable of deflecting a primary jet with a velocity of 100 m/s and a height of 50 mm by approximately 18 degrees with a momentum coefficient of 1.96%. It produces comparatively linear control characteristics in almost all deflection angles evaluated (0~23 degrees). The low pressure generated by DSJA, the ejecting enhanced by DSJA, and the co-flow effect produced by the accelerated secondary jet all play roles in the deflection of the primary jet. Since the primary jet is strong enough, the potential of DSJA to provide thrust vector control is revealed.

Dynamic stall has always been a key problem restricting the improvement of aircraft maneuverability. In this paper, the application potential of dual synthetic jets (DSJ) technology in dynamic stall control is studied. The influence of different momentum coefficients and action positions on the control effect is analyzed, and the aerodynamic control characteristics and the accompanying flow field evolution are explained. DSJ technology can improve the dynamic stall flow field environment. When the control is continuously applied at a single position throughout the pitching process, leading edge DSJ performs best, the middle DSJ is followed, and trailing edge DSJ only increases the lift during the upstroke process. Based on the above research results, a new dynamic stall control concept—the trade-off control concept is introduced, and three new control strategies, optimal control, trade-off control, and separation control, are proposed. The three control strategies have achieved better effect of increasing lift. For the whole pitching process, the average lift coefficient is increased by 19.72%, 20.98%, and 22.63%, respectively. For the downstroke process, the average lift coefficients of the three control strategies are increased by 45.30%, 48.91% and 54.56%, respectively. Among these strategies, the trade-off control concept achieves the best lift increase in the upstroke process, and the separation control concept is more effective for the control of the whole pitching process.

In order to understand the differences between dual synthetic jets (DSJs) and synthetic jets (SJs), particle image velocimetry (PIV) technology is used to capture the basic flow field characteristics of a dual synthetic jet actuator (DSJA) and a synthetic jet actuator (SJA), and then a careful comparison between them is implemented. The results indicate that a cycle of the DSJ is divided into two stages. In the near-field downstream, a pair of synthetic jets entrain fluid around them and interact with each other, making the flow field complex, and the time-periodic diaphragm dominates them. There is an unfavorable phenomenon of “self-support” between the two jets. In the far-field downstream, the two jets merge into a single, more stable SJ with a higher velocity and a double characteristic frequency. The DSJs have also shown good vectoring characteristics, with the vectoring deflection angle (VDA) changing from about −46° to 46°. The above results demonstrate that the DSJA may replace the traditional SJA in all kinds of applications and extend the applying area of the SJ to more active flow control systems, which cannot be qualified by traditional SJA.

For the purpose of turbulence drag reduction, a velocity-temperature coupled control method is proposed based on the velocity boundary layer control and the thermal boundary layer. The spatial evolution of supersonic turbulent boundary layer at a Mach number of 2.25, subject to steady blowing with different velocities and temperatures, is investigated using direct numerical simulations. Noting that the wall is isothermal with nearly adiabatic temperature, it is found that the thickness of boundary layer increases by the control of heated blowing, as do the viscous sublayer and the logarithmic zone. Moreover, drag reduction of 20.1% is achieved by heated wall blowing, higher than that of unheated wall blowing, while drag increases 12.2% by the control of cooled wall blowing. Nevertheless, the control efficiency of heated wall blowing is low due to high energy consumption, which needs further study. The reduction of mean viscous shear stress is mainly responsible for the drag reduction mechanism though there is a substantial increase in Reynolds stresses. Compressible Renard-Deck decomposition of $C_f$ indicates that it is the decrease of the spatial growth term that determines the turbulence drag reduction. The strong Reynolds analogies are still valid in all controlled cases. The average streamwise scale of near-wall streaks reduces by introducing heated blowing. Turbulence amplifications are observed in heated cases while turbulence attenuations are observed in cooled cases.