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1.
柏楠  邓学蓥  王延奎 《力学学报》2007,39(2):261-266
通过在细长旋成体模型机身的不同位置设置出烟孔,使用新型发烟装置对模型注入雾化油 滴,采用激光片光法在常规风洞中高风速(60m/s)条件下得到清晰、完整而稳定的截面涡 结构图像. 并通过同状态标定法和等比例网格法发展了简易涡位定量测量技术,为前体非对 称涡Re数效应的研究提供了重要的技术平台.  相似文献   
2.
The wing rock motion is frequently suffered by a wing-body configuration with low swept wing at high angle of attack. It is found from our experimental study that the tip perturbation and wing longitudinal locations affect significantly the wing rock motion of a wing-body. The natural tip perturbation would make the wing rock motion of a nondeterministic nature and an artificial mini-tip perturbation would make the wing rock motion deterministic. The artificial tip perturbation would, as its circumferential location is varied, generate three different types of motion patterns: (1) limit cycle oscillation, (2) irregular oscillation, (3) equilibrium state with tiny oscillation. The amplitude of rolling oscillation corresponding to the limit cycle oscillatory motion pattern is decreased with the wing location shifting downstream along the body axis.  相似文献   
3.
通过理论研究以及高频仿真相结合的方法分析设计了一款新型Ka波段8路径向波导空间功率分配(合成)器。研发的新结构输入输出段为标准矩形波导结构,代替了传统功率分配(合成)器输入输出段的同轴结构,这种新型全金属结构更加简单紧凑,更易于加工。仿真结果表明:功率分配(合成)器工作带宽达到了34%(12GHz),基本覆盖整个Ka波段;全频带内反射系数S11低于-20dB,各支路的相位差均小于5°。通过在同轴波导渐变段引入切比雪夫渐变结构,在减小了器件尺寸的同时,在整个频带内的网络S参数也不错。这款新型Ka波段8路径向波导功率分配(合成)器将应用于前级固态功率放大器,推动回旋行波管项目研发。  相似文献   
4.
低反射低吸收高平均功率输出窗的设计   总被引:2,自引:1,他引:2       下载免费PDF全文
罗勇  李宏福  徐勇  邓学  赵青 《强激光与粒子束》2004,16(11):1425-1428
 对高平均功率微波、毫米波输出窗的反射和吸收功率进行了理论分析,以蓝宝石输出窗为例,给出了低反射、低吸收的高平均功率回旋速调管放大器输出窗的设计方案。该放大器输出窗厚度为1.35mm,半径为9mm,工作频率为34GHz,在加工误差小于2%的情况下,输出窗反射率小于1%,当平均输出功率为10kW时窗片的吸收功率为2.5W。  相似文献   
5.
双阳极磁控注入枪束流特性的研究   总被引:1,自引:1,他引:0       下载免费PDF全文
 介绍了用于34GHz基波回旋速调管的双阳极磁控注入枪的结构特点,为了准确分析磁控注入枪的束流特性,建立了阴极表面理论模型,用新编制的程序模拟了电子轨迹。模拟和测量结果显示磁场对磁控注入枪的束流有影响,磁控注入枪的束流也与阴极温度和空间电荷效应有关系。  相似文献   
6.
窦华书  邓学蓥 《力学学报》1995,27(Z1):98-102
利用壁面压力测量和表面油流显示技术对后掠压缩角产生的激波与湍流边界层干扰进行了实验研究。主要研究了来流马赫数对干扰分离特性和起始分离条件的影响,实验的马赫数为1.79,2.04和2.50,相应的雷诺数为2.42—2.47×10 ̄7/m.实验模型共15个,其后掠角变化范围是0°—60°,流向压缩角变化范围是10°—30°,实验结果表明,与二维干扰不同,对于大后掠角的三维干扰来说,分离线上的压比和起始分离时的无粘激波压比近似相等,且是一个与马赫数无关的常数。  相似文献   
7.
The studies of asymmetric vortices flow over slender body and its active control at high angles of attack have significant importance for both academic field and engineering area. This paper attempts to provide an update state of art to the investigations on the fields of forebody asymmetric vortices. This review emphasizes the correlation between micro-perturbation on the model nose and its response and evolution behaviors of the asymmetric vortices. The critical issues are discussed, which include the formation and evolution mechanism of asymmetric multi-vortices; main behaviors of asymmetric vortices flow including its deterministic feature and vortices flow structure; the evolution and development of asymmetric vortices under the perturbation on the model nose; forebody vortex active control especially discussed micro-perturbation active control concept and technique in more detail. However present understanding in this area is still very limited and this paper tries to identify the key unknown problems in the concluding remarks. The project supported by the National Natural Science Foundation of China (10172017), Aeronautical Science Foundation of China (02A51048) and Foundation of National Key Laboratory of Aerodynamic Design and Research (51462020504HK0101)  相似文献   
8.
A CRITICAL PATTERN OF CROSSFLOW AROUND A SLENDER   总被引:1,自引:0,他引:1  
IntroductionModernhigh_performancefightersoftenrequiretobeoperatedunderafairlylargeangleofattacksoastoachieveexcellentmaneuverabilityandagility .Atsuchlargeangleofattack ,asymmetricallee_sidevortexflowwillformatthefrontpartofthefuselage .Sothatsuchagreats…  相似文献   
9.
10.
Topological structure and stability of a slender cross flow is discussed by the stability theory of dynamic system. The inner boundary of flow field was limiting streamline and it was proved that the topological structure connected saddles by limiting streamline is stable. It is proved that the development of slender vortices leads to the change of topological structure about cross flow. And it is the change from stable and symmetrical vortices flow pattern to unstable and symmetrical vortices flow pattern, and then to stable and asymmetrical vortices flow pattern due to little disturbance which leads to the development of asymmetrical slender vortices. The influence of disturbance to flowfield structure was discussed by unfolding theory too.  相似文献   
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