Numerical investigation of aerodynamic characteristics of a flying wing aircraft controlled by reverse dual synthetic jets

Abstract

In this work, to explore the control potential of reverse dual synthetic jets (RDSJs) in a flying wing aircraft (FWA), reverse dual synthetic jet actuators (RDSJAs) are integrated into a FWA with a hybrid flow mode of rollers and streamers. The aerodynamic characteristics and control mechanism are investigated using numerical simulations. The results show that the aerodynamic loads follow a nonlinear trend, and the overall process can be divided into three stages with an increasing angle of attack (AOA). In the first stage (AOA = 0°–8°), the RDSJs can improve the reverse pressure gradients and form alternate recirculation zones or even a large-area separation. The pressure rises before and falls after the exits, causing an increase in Cd and a drop in CL. The decrease in the leading-edge suction and the pressure envelope area results in a further increase with the increasing AOA, resulting in a reduction in ΔCL and an improvement in ΔCd. In the second stage (AOA = 8°–24°), the energy of the RDSJs is too low to form a strong disturbance over the leeward surface, and the promotion of favorable pressure gradients along the lower surface can weaken the control effects of the RDSJAs, causing a decrease in the narrowing degree of the pressure envelope. The leading-edge vortex (LEV) is weakened, and ΔCL increases as Cd experiences a drop. In the third stage (AOA = 24°–32°), the RDSJs interact with the larger separation and are capable of accelerating the flow over the wing section, elevating the longitudinal velocity of the LEV through entrainments and improving the strength and stability of the LEV. The accelerated flow creates negative pressures behind RDSJAs, causing a further reduction in the decrement of the pressure envelope area. An enhancement of CL and Cd appears under the influence of the above factors.