对高层体系结构(HLA)的剖析

高层体系结构(HLA)着眼于仿真应用之间互操作和仿真应用的重用，从而大大改善综合仿真环境的有效性和经济性，并且促进分布交互式仿真(DIS)的发展。但是，HLA并非尽善尽美，有待日臻完善。     

大范围运动刚柔耦合系统动力学建模与仿真

以往对刚柔耦合系统的控制研究多是基于传统零次近似动力学模型,当系统存在大范围运动时,零次近似动力学模型已不能正确揭示动力学行为.从连续介质力学的基本原理出发,在变形位移的描述中计及二次耦合项,同时忽略轴向拉伸量,得到更符合实际控制需要的简化一次近似动力学模型.仿真结果表明,该模型正确预示了系统的动力学行为;与传统一次近...     

Deriving remote sensing reflectance from turbid Case II waters using green-shortwave infrared bands based model

The objectives of this study are to validate the applicability of a shortwave infrared atmospheric correction model (SWIR-based model) in deriving remote sensing reflectance in turbid Case II waters, and to improve that model using a proposed green-shortwave infrared model (GSWIR-based model). In a GSWIR-based model, the aerosol type is determined by a SWIR-based model and the reflectance due to aerosol scattering is calculated using spectral slope technology. In this study, field measurements collected from three independent cruises from two different Case II waters were used to compare models. The results indicate that both SWIR- and GSWIR-based models can be used to derive the remote sensing reflectance at visible wavelengths in turbid Case II waters, but GSWIR-based models are superior to SWIR-based models. Using the GSWIR-based model decreases uncertainty in remote sensing reflectance retrievals in turbid Case II waters by 2.6–12.1%. In addition, GSWIR-based model’s sensitivity to user-supplied parameters was determined using the numerical method, which indicated that the GSWIR-based model is more sensitive to the uncertainty of spectral slope technology than to that of aerosol type retrieval methodology. Due to much lower noise tolerance of GSWIR-based model in the blue and near-infrared regions, the GSWIR-based model performs poorly in determining remote sensing reflectance at these wavelengths, which is consistent with the GSWIR-based model’s accuracy evaluation results.     

Characteristics of the seasonal variation of the global tropopause revealed by COSMIC/GPS data

Using the Global Navigation Satellite System (GNSS) radio occultation observations from Formosa Satellite mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC) from 2007 to 2012, the climatological characteristics of the global tropopause was studied, with the following features identified. The overall results generally agree with previous studies. The tropopause has an obvious zonal structure, with more zonal characteristics in the Southern Hemisphere than the Northern Hemisphere. The vertical shape of the tropopause is sharp in the tropics and broad in the sub-tropical latitudes, with the sharpest latitudinal gradient in the mid-latitudes of both hemispheres. The global tropopause exists in a large range between 8 km and 17 km (or between 100 hPa and 340 hPa). The highest tropopause is over the South Asian monsoon regions for the entire year. The spatial structure of the tropopause in the polar region is of concentric structure, with an altitude between 7.5 km and 10 km. It is more symmetric in the Antarctic than the Arctic. Differing from other places, the height of the tropopause in the Antarctic is higher in winter as opposed to summer. The tropopause has distinct seasonal variability, especially in polar regions.     

双旋流空气雾化喷嘴喷雾、流动和燃烧性能

 综述了现代燃烧室广泛使用的双旋流空气雾化喷嘴的关键设计参数以及工况对装该种喷嘴的燃烧室性能的影响。双旋流空气雾化喷嘴的关键设计参数包括双旋流器、文氏管、套筒的结构、旋流器的旋流数、套筒张角、文氏管与套筒的相对尺寸等,这些参数与燃烧室主燃孔一起作用,控制了该喷嘴的喷雾和流动特性,从而控制着燃烧特性,如点火、熄火及燃烧效率等。这些讨论为设计该类结构燃烧室打下理论和经验方面的基础,是优化和提高这种类型燃烧室的性能的重要参考。     

航天器轨道控制系统的智能设计方法与仿真

本文介绍了将智能控制方法用于航天器交会对接段的轨道控制。通过建立系统的特征模型、知识库、数据库和规则库并且构造出相应的推理机构和控制逻辑,为航天器的轨道控制过程设计了一种专家式智能控制器。仿真结果表明了此系统具有较好的跟踪性能。     

有轴向通流的双旋转轴间流动换热的数值模拟

采用混合长度模型,用共轭数值计算的方法研究了具有轴向通流且内轴加热情况下的双旋转轴间的换热,得到了内轴、双轴间隙内的温度场,内轴外壁面的温度分布情况,内轴外壁面对流换热系数的分布情况,并与实验结果进行了比较,结果表明:经过修正的混合长度模型对具有轴向通流的双旋转轴间换热情况的计算是可行的.      

飞机内部腐蚀关键部位加速试验环境谱研究

为进行飞机结构日历寿命体系评定,针对某型飞机机体结构内部腐蚀关键部位,对其加速腐蚀试验环境谱进行了研究。提出了适用于内部结构腐蚀关键部位的加速腐蚀试验环境谱,并进行了加速腐蚀试验,采用腐蚀程度对比法确定了加速腐蚀试验环境谱与实际飞机使用环境之间的当量关系,并已成功地将其应用到歼X型飞机机体结构的日历寿命评定中。     

使用VSCMGs的IPACS的奇异性分析与操纵律设计

 研究使用变速控制力矩陀螺群(VSCMGs)的能量/姿态一体化控制系统(IPACS)的奇异性分析与操纵律设计问题。提出了VSCMGs的CMG奇异与IPACS奇异两种概念。对于给定的CMG奇异方向,采用优化理论得到了在该方向上VSCMGs的转子达到角动量饱和时的转速表达式,并给出了IPACS奇异的充要条件及其证明。分析了考虑星体角速度影响时的实际IPACS的奇异性质。在此基础上为实现合理的动量管理,采用加权矩阵的方法设计了IPACS的操纵律。最后通过算例验证了所得到的IPACS奇异判据的正确性,并通过数值仿真,验证了所设计的操纵律的正确性及其良好的动量管理性能。     

液体火箭发动机动态数据处理的小波分析方法

研究了基于小波分析的液体火箭发动机动态数据处理方法，给出了数据处理模型，应用小波奇异性检测和误差滤波理论，分析了动态数据的处理过程，并用某液体火箭发动机某次地面试车的动态测试数据进行了验证。结果表明，小波分析方法不需要过程误差的先验知识，能够同时完成异常数据的检测及相应误差的滤除任务，非常适合于液体火箭发动机的动态工作过程。