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In order to meet the demanding drag reduction requirements of high-speed aircraft, the drag reduction mechanism of array microslit-opposed jets in the passivation leading edge is studied using a numerical method based on the shear stress transfer (SST) k-ω two-path turbulence model. The computations are performed with the commercial CFD solver FLUENT 13.0 code. The interference characteristics of the array jets are analyzed, the influence laws of the microslit array mode and the angle of attack on drag reduction performance are explored, and a prediction method of passivation leading edge drag characteristics based on radial basis function (RBF) neural network is constructed. The research conditions are as follows: the incoming Mach number is 2.0, the angle of attack ranges from 0° to 30°, and the number of microslits is 0 to 5. The results show that when there is interference between microslit jets, the interaction between adjacent reverse reflux regions will change the shape of the reflux regions. When there is a microslit jet in the center line, the position of the detached shock wave is more affected by the angle of attack. The drag characteristics of the leading edge are determined by the location of the detached shock wave and the characteristics of the reflux regions. The mode of microslits determines the drag reduction efficiency and sensitivity to the angle of attack. There may be contradictions in the design of array microslit-opposed jet schemes regarding the overall drag reduction efficiency, local load, and drag reduction stability. The drag prediction model based on the RBF neural network has an accuracy of 5%, which can provide support for the design of array microslit-opposed jets. Practical Applications: The array microslit-opposed jets provide a new technical approach for reducing drag on the passivation leading edge. The paper studies its flow characteristics and laws and provides relevant conclusions. It can serve as a theoretical reference during design. The number of microslits is not the more the better. When designing microslit patterns, many factors need to be considered. [ABSTRACT FROM AUTHOR]

This paper presents a new control surface, which we have named auxiron, that helps a solar-powered aircraft to orient itself according to the position of the sun in the sky to collect more solar power. The auxiron also enables an aircraft to land in crosswind conditions with no or reduced sideslip angle depending on the auxiron control power. The auxiron serves to produce the necessary side aerodynamic force for counterbalancing the horizontal component of the lift force. Its primary purpose is to eliminate the sideslip angle during flight with a nonzero bank angle. This results in a reduction in aerodynamic drag and power consumption required to maintain a straight-line flight with nonzero bank angles. By implementing this innovative control surface, an aircraft can now cruise straight without experiencing any sideslip angle, even with nonzero bank angles. The modified stability and control derivatives for the aircraft configuration with the auxiron are established, and these derivatives are incorporated into the aircraft dynamics. The 6-DoF simulation is carried out for the solar UAV, Maraal, which demonstrates the effectiveness of the auxiron. [ABSTRACT FROM AUTHOR]