Based on the linear displacement motion similarity and angular displacement motion similarity, the similarity law for free flight test of light store separation from aircraft is deduced. The problem that the ideal test model is too light to be processed and the free flight separation test in wind tunnel is harder to achieve due to the model scaling is solved. The new similarity law was simplified reasonably, and the relationship equation between separation velocity and model mass was obtained. The wind-loaded state is simulated by computational fluid dynamics, and the real separation data of aircraft, the separation data of previous test methods, and the simulation data of different mass and different separation velocity trajectories of this similarity law are obtained. The improved effect of the new similarity law is verified by data comparison. The results show that by properly increasing the mass of wind tunnel test model, the difficulty of wind tunnel test can be greatly reduced while the separation trajectory is similar, and the angular displacement error can be guaranteed to be within acceptable range. In order to ensure better consistency between flight and free flight wind tunnel test, it solves the problem that similarity law can only be designed but cannot be realized.
In view of the control effects of fluidic thrust vector technology for low-speed aircraft at high altitude/low density and low altitude/high density are studied. The S-A model of FLUENT software is used to simulate the flow field inside and outside the nozzle with variable control surface parameters, and the relationship between the area of control surface and the deflection effect of main flow at different altitudes is obtained. It is found that the fluidic thrust vectoring nozzle can effectively control the internal flow in the ground state and the high altitude/low density state. and the mainstream deflection angle can be continuously adjusted. The maximum deflection angle of the flow in the ground state is 21.86°, and the maximum deviation angle of the 20 km high altitude/low density state is 18.80°. The deflecting of the inner flow of the nozzle is beneficial to provide more lateral force and lateral torque for the aircraft. The high altitude/low density state is taken as an example. When the internal flow deflects 18.80°, the lateral force is 0.32 times the main thrust. For aircraft with high altitude and low density, sufficient lateral and lateral torque can make the flying aircraft more flexible, which can make up the shortcomings of the conventional rudder failure and even replace the conventional rudder surface.
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