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Fighter aircraft often require unconventional maneuverability that civil aircraft cannot perform. The conventional flight control devices are not sufficient for this maneuver. Thus, to be able to perform unconventional maneuvers, additional control devices may be required, such as the thrust vectoring system (TVS). This paper will discuss the effect of TVS implementation in improving maneuverability. In this work, a dynamic model of F-4 Phantom is used as the basis for the study. The dynamic model of the aircraft with TVS is constructed analytically and numerically. The nonlinear model obtained from the modeling process then linearized at a particular flight condition and some TVS deflection values. Further, the linear system and control approach is employed for evaluating and designing the linear controllers for stabilization and maneuvering tasks. The closed-loop system, which is implemented in the MATLAB/Simulink environment, then numerically simulated and observed for analyzing the effect of implementing different TVS deflection on the required control effort in high angle of attack maneuvers. The simulation results show that the TVS can affect the performance of the closed-loop system in stabilization tasks. While at some deflection values, TVS can also help to reduce the required control effort to tracking attitude reference command when executing the high angle of attack maneuvers.

Aiming at the problems that the performance of the mechanism at high angle of attack in 2.4m transonic wind tunnel (hereinafter referred to as 2.4m wind tunnel) is degraded, and the stability and positioning accuracy of the mechanism can not meet the test requirements during operation, the motion control system of the mechanism is redeveloped, and a bidirectional control algorithm is designed, which effectively solves the problems of running jitter and poor positioning accuracy of the mechanism at high angle of attack. The system has been put into use in 2.4m wind tunnel at high angle of attack, and the results show that the application effect is well.

Airfoil slots, as a passive flow control technique-based wing improvement structure, may successfully delay the stall angle and increase the lift coefficient in situations with a high angle of attack. But when the angle of attack is minimal, it drastically reduces the airfoil’s initial aerodynamic performance. The NACA4412 airfoil is used as the research object in this study, which uses Computational Fluid Dynamics (CFD) techniques to examine how various slot configurations affect the airfoil’s aerodynamic properties. Based on the optimal slot configuration, a scheme for dynamically adjusting the slot angle is proposed. The research results demonstrate the following: 1) Compared to previous configurations, Slot Configuration III may greatly enhance the airfoil’s stall characteristics by postponing the stall angle to 24° and raising the maximum lift coefficient by 27.6% to 1.57; 2) Through the rotation of the leading edge, the study achieved changes in slot configuration and inlet/outlet parameters, resulting in two slot configurations capable of maintaining aerodynamic performance under small angles of attack; 3) Utilizing the geometric relationship between Slot Configurations III and IV (5°, 8°), a variable-angle slot scheme is proposed, which enhances small angle of attack lift while effectively suppressing stall phenomena.

Compared to the traditional method of adjusting flight time by increasing lateral maneuverability [1-2], a faster time-coordinated longitudinal guidance method for unpowered high-speed vehicles has been proposed in this paper. Firstly, the centroid dynamics model and flight constraint model of unpowered high-speed vehicles were established, and the angle of attack corridor was derived based on quasi-equilibrium gliding conditions (QEGC). Then, to plan a reasonable angle of attack profile, the flight capability of a single vehicle under different constant angles of attack is analyzed, including terminal altitude, terminal velocity, and terminal arrival time. Furthermore, to achieve a long-term high angle of attack flight, a rapid time-coordinated longitudinal guidance method based on a trapezoidal angle of attack profile was proposed. Finally, using the vehicle and its performance parameters from Chapter 3 [3], numerical simulations were conducted under nominal tasks and multi-vehicle collaborative tasks. The simulation results show that under different expected arrival times, this method can quickly plan the angle of attack profile that satisfies time constraints, with high computational efficiency. Moreover, the arrival time adjustment ability of this method is large, which can fully utilize the arrival time capability of the high-speed vehicle. The above research provides more convenient conditions for a collaborative flight of multiple vehicles.

When a submarine encounters an emergency situation, it should take emergency-surfacing actions by moving upward with a large angle of attack in the vertical plane. Previous research has often neglected the effect of vertical plane motion on the lateral force (Fy), rolling moment (Mx), and yawing moment (Mz). To examine the flow characteristics of submarines at high angles of attack on the vertical plane, the SST-DDES method is adopted in conjunction with adaptive mesh refinement (AMR) technology, and the new Omega vortex detection method is employed as the AMR criterion for numerical calculations. The obtained results are then appropriately verified by conducting water tank experiments, and the effects of different angles of attack and heel angles on Fy, Mx, and Mz are methodically examined. The results reveal that, in the flow around the vertical plane of a submarine, the influence of Fy and Mz cannot be ignored. In addition, when the vertical velocity of the hull is greater than 0.6 m/s, the influence of Mx cannot be overlooked either. When the angle of attack on the vertical plane of the submarine is greater than 25°, the effects of Fy, Mx, and Mz cannot be neglected, and the effect of Mz is particularly prominent, with its amplitude close to or greater than the average value of the pitch moment (My). The obtained results reveal that the presence of the heel angle (θ) intensifies the forces on the hull for Fy, Mx, and Mz, and the forces caused by the vertical velocity at Fy, Mx, and Mz cannot be neglected. These findings can provide a mechanical analysis basis for the analysis of nonlinear motion phenomena during submarine surfacing.

For a distributed tilt-power configuration aircraft, the transition corridor was studied based on limited conditions such as wing lift characteristics and propeller power requirement. By establishing the dynamic model of each component and balancing according to the balance equation, the boundary of the transition corridor of distributed tilting dynamic configuration is determined. The results show that the minimum forward flight speed required for a low Angle of attack is less than that for a high Angle of attack; the wing lift characteristic high-speed boundary and the propeller power limit boundary together form the high-speed boundary of the transition corridor.

High-altitude wind energy is widely distributed, and parachutes have great potential to capture them. This paper focuses on the aerodynamic inflation process of a high-altitude parachute at a high angle of attack, which is essential for wind energy harvest. First, the arbitrary Lagrangian-Eulerian method (ALE) method is verified by simulating the main inflation phase of the C-9 parachute. Good agreements with the experimental data are achieved quantitatively. Then, numerical simulations of the inflation process of a parachute with an attack angle of 35°and a wind speed of 20ms −1 at an altitude of 1500m high are carried out. The evolution of the morphology of the parachute, the stress distribution, and the flow field characteristics are demonstrated and discussed.

This study’s primary goal is to investigate how various airfoils’ maximum camber positions affect hydrofoil cavitation performance. Through numerical simulation, the cavitation low properties of hydrofoils with various maximum camber positions are compared. The accuracy of the modi ied turbulence viscosity and SST k-ω turbulence model on the temporal and spatial evolution characteristics of cavitation near the hydrofoil is evaluated by combining it with the model test. Analysis is done on the cavitation low ield of four airfoils at two distinct design angles of attack (+4° and +6°) with varying maximum camber locations (fmax = 35%C, 40%C, 50%C, and 60%C). The indings indicate that at 35%C, the hydrofoil’s maximum camber position has improved cavitation performance. The hydrofoil’s cloud cavitation evolution time is shorter than that of the original hydrofoil, and during the same time period, more cavitation is generated. The lift-to-drag ratio and lift coef icient of the cavitation low ield are signi icantly improved at both angles of attack. At the same time, the vorticity distribution and entropy generation distribution can be effectively reduced under the design angle of attack and high angle of attack cavitation, and the hydraulic loss in the cavitation low ield can be reduced. This research can serve as a guide for optimizing the hydrofoil’s cavitation performance and designing the impeller of the axial low pump that follows.

This paper describes the advantages and disadvantages and principle of passive side stick and active side stick respectively. A redundant architecture of active side stick control system is proposed according to top-level function and safety requirements. The control unit with active-standby control channels, which has dissimilar command-monitoring hardware, can significantly improve the safety performance. Finally, the high angle of attack protection and high-speed protection of active side stick control system has been tested on one civil aircraft simulation platform, and it proves that the active side stick control system can effectively realize the tactile and warning function of envelope protection.

The slender body is selected as the shape of the study. The effects of lateral jet flow at M ∞ = 0.3, 0.6, 0.8 on the asymmetric separation characteristics of the body at large angles of attack are numerically simulated. To obtain the deterministic asymmetric separation results of the slender body, the artificial disturbance is carried on the tip of its head. The aerodynamic characteristics of asymmetric separation in jet-off and jet-on conditions are obtained, and the effects of Mach number, Angle of attack on asymmetric separation flow behaviors of the slender body are analyzed.