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31.
By using the mesh resolution control method based on the nozzle scale, a paralleled super numerical simulation and high-quality mesh model of the launch jet dynamics for new-generation launch vehicles was developed.Based upon this, a transient numerical simulation method, combining the pressure and velocity, tightly coupled algorithm and SST turbulence model, was used to complete the unsteady numerical simulation of the launch jet dynamics of the new-generation launch vehicles. The numerical sim... 相似文献
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In this paper, Active Disturbance Rejection Control(ADRC) is utilized in the pitch control of a vertical take-off and landing fixed-wing Unmanned Aerial Vehicle(UAV) to address the problem of height fluctuation during the transition from hover to level flight. Considering the difficulty of parameter tuning of ADRC as well as the requirement of accuracy and rapidity of the controller, a Multi-Strategy Pigeon-Inspired Optimization(MSPIO) algorithm is employed. Particle Swarm Optimization(PSO), Gen... 相似文献
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A new algorithm for dimension variation of feature-based models is developed.The algorithm is based on B-Rep/CSG hybrid scheme and operates directly on B-Rep.Product information (including the features locating dimensions and other data for manufacture) will not lose after model variation and modification.Furthermore, the definition and solution of features constraints are also supported.The scheme of directly operating on B-Rep overcomes many drawbacks of other proposed methods, most of which need to redo all of the previous work to implement dimension variation, so the computational cost is expensive and product information will lose.What is presented in this paper makes a new way in the area of parametric design. 相似文献
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As the low temperature non-equilibrium plasma, microwave plasma has the same effects with the plasma produced by the traditional high voltage electrode, which has the function of widening ignition boundary and improving combustion. Microwave has the advantages of uniformity, particle selectivity and no electrode. It can generate a large range of non-equilibrium plasma with relatively low power without electrode ablation. Therefore, how to maximize its effectiveness has become the research hotspo... 相似文献
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The development of Chinese space science and technology plays a great role in promoting the researches in the field of the origin of life. With the multidisciplinary cooperation, there are fruitful achievements in this research field obtained over the past two years. This report summarizes the major progress of the basic researches about the origin of life in China during 2018-2020. 相似文献
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Xinlei PAN Weifeng HE Zhenbing CAI Xuede WANG Ping LIU Sihai LUO Liucheng ZHOU 《中国航空学报》2022,35(4):521-537
Titanium alloys have a wide application in aerospace industries as it has greater strength and low density, but it has poor tribological properties. To improve its friction and wear performance, in present work, a femtosecond laser is used to directly irradiate the Ti6Al4V titanium alloy surface in air conditioning, which results in localized ablation and the formation of periodic microstructures but also a strong pressure wave, propagating the material inside. Through the optimization of proces... 相似文献
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The kinematic characteristics of flexible membrane wing have vital influences on its aerodynamic characteristics. To deeply explore the regularities between them, time-resolved aerodynamic forces and deformations at different aeroelastic parameters and angles of attack(α) were measured synchronously by wind tunnel experiments. The membrane motion can be mainly divided into two states at α > 0° with various lift-enhancement regularities: Deformed-Steady State(DSS)at pre-stall, and Dynamic Bala... 相似文献
38.
Ao HE Honggang GAO Shanshan ZHANG Zhenghong GAO Bodi MA Lulu CHEN Wei DAI 《中国航空学报》2022,35(10):95-105
The Stopped-Rotor(SR) UAV combines the advantages of vertical take-off and landing of helicopter and high-speed cruise of fixed-wing aircraft. At the same time, it also has a unique aerodynamic layout, which leads to great differences in the control and aerodynamic characteristics of various flight modes, and brings great challenges to the flight dynamics modelling and control in full-mode flight. In this paper, the flight dynamics modelling and control method of SR UAV in full-mode flight is st... 相似文献
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During the past two years (2016-2018), great achievements have been made in the Chinese research of interplanetary physics, with nearly 100 papers published in the academic journals. The achievements are including but not limited to the following topics:solar corona; solar wind and turbulence; filament/prominence and jets; solar flare; radio bursts; particle acceleration at coronal shocks; magnetic flux ropes; instability; instrument; Coronal Mass Ejections (CMEs) and their interplanetary counterparts; Magnetohydrodynamic (MHD) numerical modeling; solar energetic particles and cosmic rays. The progress further improves our understanding of the eruptions of solar activities, their evolutions and propagations in the heliosphere, and final geoeffects on our Earth. These results were achieved by the Chinese solar and space scientists independently or via international collaborations. This paper will give a brief review of these achievements. 相似文献