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91.
92.
针对舰空导弹协同制导仿真系统的设计问题,通过给定舰舰协同和空舰协同这两种典型协同制导作战模式的作战流程,对仿真系统的组成及组成单元的模型构成进行了深入的分析。基于高层体系结构HLA(High Level Architecture)分布式仿真技术,对分布式半实物的协同制导仿真系统进行了方案设计,并且通过采用实时操作系统内核和半实物仿真代理联邦成员的方法,有效地解决了半实物仿真的实时性要求和半实物仿真与分布式仿真的互操作等关键问题。 相似文献
93.
The method of reliability is proposed for the investigation of thermal contact conductance (TCC) in this study. A new definition is introduced, namely reliability thermal contact conductance (RTCC), which is defined as the TCC value that meets the reliability design requirement of the structural materials under consideration. An experimental apparatus with the compensation heater to test the TCC is introduced here. A practical engineering example is utilized to demonstrate the applicability of the proposed approach. By using a statistical regression model along with experimental data obtained from the interfaces of the structural materials GH4169 and K417 used in aero-engine, the estimate values and the confidence level of TCC and RTCC values are studied and compared. The results show that the testing values of TCC increase with interface pressure and the proposed RTCC model matches the test results better at high interface pressure. 相似文献
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95.
《中国航空学报》2021,34(7):170-186
Humans' initial desire for flight stems from the imitation of flying creatures in nature. The excellent flight performance of flying animals will inevitably become a source of inspiration for researchers. Bio-inspired flight systems have become one of the most exciting disruptive aviation technologies. This review is focused on the recent progresses in bio-inspired flight systems and bionic aerodynamics. First, the development path of Biomimetic Air Vehicles (BAVs) for bio-inspired flight systems and the latest mimetic progress are summarized. The advances of the flight principles of several natural creatures are then introduced, from the perspective of bionic aerodynamics. Finally, several new challenges of bionic aerodynamics are proposed for the autonomy and intelligent development trend of the bio-inspired smart aircraft. This review will provide an important insight in designing new biomimetic air vehicles. 相似文献
96.
Saurabh Das Ashish K. Shukla Animesh Maitra 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The microstructure of rain has been studied with observations using a vertical looking Micro Rain Radar (MRR) at Ahmedabad (23.06°N, 72.62°E), a tropical location in the Indian region. The rain height, derived from the bright band signature of melting layer of radar reflectivity profile, is found to be variable between the heights 4600 m and 5200 m. The change in the nature of rain, classified on the basis of radar reflectivity, is also observed through the MRR. It has been found that there are three types of rain, namely, convective, mixed and stratiform rain, prevailing with different vertical rain microstructures, such as, Drop Size Distribution (DSD), mean drop size, rain rate, liquid water content and average fall speed of the drops at different heights. It is observed that the vertical DSD profile is more inhomogeneous for mixed and stratiform type rain than for convective type rain. It is also found that the large number of drops of size <0.5 mm is present in convective rain whereas in stratiform rain, drops concentration is appreciable up to 1 mm. A comparison of measurements taken by ground based Disdrometer and that from the 200 m level obtained from MRR shows good agreement for rain rate and DSD at smaller rain rate values. The results may be useful for understanding rain structures over this region. 相似文献
97.
无需先验信息的水平集SAR图像分割方法 总被引:1,自引:0,他引:1
给出了一种基于水平集演化、无需任何先验信息的SAR图像分割方法.该方法是一种基于区域信息的统计活动轮廓模型方法,通过利用分段阶跃函数估计图像概率密度函数,克服了利用特定概率分布模型估计概率密度函数时,需要利用先验信息预先假定图像概率分布模型的问题;通过引入惩罚项,避免了费时且难于操作的水平集函数重新初始化过程.还给出了具体的数值实现方案和相关参数取值,改进了数值实现中的迭代终止条件.实验结果表明,固定使用列出的参数,无需任何人为干预,对于大多数图像都可获得令人满意的分割结果;对于少数图像,通过简单的参数调整也可得到良好结果. 相似文献
98.
针对航天嵌入式系统中存在多级中断情况下的时间分析问题,提出了中断与任务混合的响应时间计算模型。该模型中断与任务使用统一的优先级定义,将多级中断嵌套的响应时间分析与任务嵌套的响应时间分析相结合,推导出了混合模型下响应时间计算公式。并进一步比较了中断与任务的异同,阐述了公式中关键参数的含义与计算方法。最后利用开源的LEON3平台和Modelsim软件对所述方法进行了仿真验证,结果表明,任务最差响应时间过估小于5%,可以得到准确的分析结果,有较高的工程应用价值。 相似文献
99.
N.I. Ismail A.H. Zulkifli M.Z. Abdullah M. Hisyam Basri Norazharuddin Shah Abdullah 《中国航空学报》2013,26(5):1093-1105
Abstract Implementing the morphing technique on a micro air vehicle (MAV) wing is a very chal- lenging task, due to the MAWs wing size limitation and the complex morphing mechanism. As a result, understanding aerodynamic characteristics and flow configurations, subject to wing structure deformation of a morphing wing MAV has remained obstructed. Thus, this paper presents the investigation of structural deformation, aerodynamics performance and flow formation on a pro- posed twist morphing MAV wing design named perimeter reinforced (PR)-compliant wing. The numerical simulation of two-way fluid structure interaction (FSI) investigation consist of a quasi- static aeroelastic structural analysis coupled with 3D incompressible Reynolds-averaged Navier- Stokes and shear-stress-transport (RANS-SST) solver utilized throughout this study. Verification of numerical method on a rigid rectangular wing achieves a good correlation with available exper- imental results. A comparative aeroelastic study between PR-compliant to PR and rigid wing per- formance is organized to elucidate the morphing wing performances. Structural deformation results show that PR-compliant wing is able to alter the wing's geometric twist characteristic, which has directly influenced both the overall aerodynamic performance and flow structure behavior. Despite the superior lift performance result, PR-compliant wing also suffers from massive drag penalty, which has consequently affected the wing efficiency in general. Based on vortices investigation, the results reveal the connection between these aerodynamic performances with vortices formation on PR-comoliant wing. 相似文献
100.