训练飞行中指挥席位资源管理

训练飞行不同于航空公司运输飞行,具有训练科目复杂、机组技术水平各异、低空飞行气象要素复杂等特点。本文在考虑训练飞行的特殊性及人的因素等因素影响的同时,利用现有资源对训练指挥席位进行资源管理。     

新媒体视域下系统构建“三位一体”公寓管理模式

随着科技日益进步和5G时代的即将到来,在治理体系上越来越注重管理与哲学教育相结合,高校作为接收新事物、新思维的前沿阵地。学生公寓成为大学生思想政治教育的又一个重要的阵地,因此创新公寓管理体系并努力做到使之与哲学相结合也成为了一项重大任务,高校辅导员、公寓辅导员、高校后勤管理人员结合新媒体创新学生公寓的管理方式对新时代大学生的教育、管理、服务掌控和开展思想政治教育工作至关重要。     

泰雷兹:让中法的天空更加通畅

正中国民用航空局空中交通管理局局长车进军表示:"从简单设备的引进,大型设备的引进,人员的培训到技术的合作,中法航空50年空管发展的历程见证了合作的加深,合作的广泛,合作的成功。"2016年是中国与法国之间开通航线50周年,也是中法航空合作50周年。在民航技术合作板块,中法两国在民航空管领域的合作最具代表性。     

Drag Reducing and Increasing Mechanism on Triangular Riblet Surface

Drag reducing and increasing mechanism on riblet surface has been studied through computational fluid dynamics(CFD).Drag reduction is achieved through the optimization of riblet geometry which would affect flow structure inside riblet grooves.Force and flow structure on riblet surface are analyzed and compared with those of smooth surface based on the k-εturbulence model.Drag reducing and increasing mechanism is proved to be related to microvortexes induced inside riblets which lead to Reynolds shear stress reduction significantly and is considered to be the dominant factor resulting in wall friction reduction.Simulation results also show that the pressure drag generating from the deviation of static pressure on the front and rear ends of riblets occurs and grows exponentially with Mach number,which can cause drag increasing.Furthermore,near-wall vortical structures,Reynolds shear stress and static pressure on riblet surfaces are also analyzed in detail.     

Early analysis of precise orbit and clock offset determination for the satellites of the global BeiDou-3 system

Eight new-generation BeiDou satellites (BeiDou-3) have been launched into Medium Earth Orbit (MEO), allowing for global coverage since March 2018, and they are equipped with new hydrogen atomic clocks and updated rubidium clocks. Firstly, we analyzed the signals for the carrier-to-noise-density ratio (C/N0) and pseudorange multipath (MP) by using international GNSS (Global Navigation Satellite System) Monitoring and Assessment System (iGMAS) station data, and found that B1C has a lower C/N0, and B2a has the same level of C/N0 as the B1I and B3I signals. For pseudorange multipath, compared with the BeiDou-2 satellites, the obvious systematic variation of MP scatters related to the elevation angle is greatly improved for the BeiDou-3 and BeiDou-3e satellites signals. For the signals of the BeiDou-3 satellites, the order of the Root Mean Square (RMS) values of multipath and noise is B3I?<?B1I?<?B2a?<?B1C. Then, the comparison of the precise orbit determination and clock offset determination for the BeiDou-2, BeiDou-3, and BeiDou-3 experimental (BeiDou-3e) satellites was done by using 10 stations from iGMAS. The 3D precision of the 24?h orbit overlap is 24.55, 25.61, and 23.35?cm for the BeiDou-3, BeiDou-3e, and BeiDou-2 satellites, respectively. BeiDou-3 satellite has a comparable precision to that of the BeiDou-2 satellite. For the precision of clock offset estimation, the Standard Deviation (STD) of the BeiDou-3 MEO satellite is 0.350?ns, which is an improvement of 0.042?ns over that of the BeiDou-2 MEO satellite. The stabilities of the BeiDou-3 and BeiDou-3e onboard clocks are better than those of BeiDou-2 by factors of 2.84 and 1.61 at an averaging time of 1000 and 10,000?s, respectively.     

高超声速圆锥边界层失稳条纹结构实验研究

边界层转捩的准确预测是高超声速飞行面临的关键气动问题之一。为研究高超声速边界层失稳和转捩机理,以前缘半径1.6mm、半锥角7°的圆锥模型为研究对象,在FD-07高超声速风洞中采用红外热图技术开展边界层转捩实验测量。通过与工程计算结果对比,确认模型表面边界层流态。实验结果表明:有迎角条件下,模型表面中后段出现条纹结构,条纹结构的起始位置随着周向角的增加而向上游移动;随着迎角的增加,条纹起始位置向上游移动,条纹强度差异和条纹与模型中心线的夹角越来越大。实验获得的条纹结构与不同频率扰动波相互作用直接数值模拟获得的条纹结构现象一致。通过对比分析,认为边界层内不同频率扰动波相互作用是产生条纹结构的一种机制。