梢涡空泡初生预报方法

应用气泡动力学方程和气泡运动微分方程研究了梢涡空泡的初生问题.建立了球形气泡平均压力模型,通过模拟梢涡流场中的球形气泡形态对梢涡空泡的初生进行预报.应用平均压力模型分别计算了三种尺度水翼梢涡流场中不同初始尺寸气泡在一定时间内的半径和辐射声压,梢涡用轴向梢涡尺寸不变的兰金涡代替.计算结果表明:从光学法和声学法角度选取空化...     

基于SD流率基本入树的部队装备管理信息化建设研究

部队装备管理信息化建设是当前我军装备管理领域正在着力进行的一项复杂系统工程。深入探索建设规律,对于指导建设实践、提高建设质量具有重要意义。在对部队装备管理信息化建设进行系统分析的基础上,利用系统动力学（SD）流率基本人树建模方法构建了其流率基本人树模型,并利用vensim仿真软件对其进行了实例仿真。研究表明,运用系统动力学方法可以实现对部队装备管理信息化建设问题的研究由定性向定量转变,深化规律探索,同时研究结果也可为建设决策提供科学的定量理论支持。     

Facility location for an extraterrestrial production/distribution system

This paper extends traditional production/distribution system analysis to address raw material, factories, and markets located beyond Earth. It explains the eventual advantages of such operations and discusses likely sites in the solar system. It furnishes a typology for production/distribution systems, assessing the fit of each type to space operations. It briefly reviews the physics of orbits. It develops transportation and inventory cost functions for the simplest case of Hohmann trajectories, and for transportation between circular orbits of similar radii using higher‐energy trajectories. These cost functions are used to derive a model of production/distribution system cost, the minimization of which selects an optimal factory location. The paper suggests potential extensions to this work, and concludes with ideas for location research on the novel reaches of extraterrestrial space. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

系统动力学C3I系统作战效能评估

C3I系统效能评估是C3I系统发展的重要问题,现有的ADC法、指数法、层次分析法和SEA方法等都存在着某种局限性,也无法度量C3I系统与作战结果的关系.系统动力学是一门分析研究信息反馈系统的学科,适合于研究C3I系统的系统效能和作战效能之间的定量关系.以一个具体的关于C3I系统的作战想定为例,构建了该C3I作战系统的因...     

基于X射线脉冲星的Halo轨道卫星自主导航和控轨

讨论x射线脉冲星自主导航（X—raypulsar-basedautonomousnavigation,XNAV）技术应用于halo轨道卫星的可行性。给出halo轨道卫星的6维状态方程和基于x射线脉冲星导航的6维观测方程,对用x射线脉冲星导航和小推力方法控轨后的日地系第一平动点halo轨道卫星进行了数值模拟。结果表明：在现有的测量精度下,可以将卫星保持在标准轨道附近。最后对实验参数数值的选择给出了相应的分析讨论。     

载机军舰航空燃油分段接力式补给模型

为解决载机军舰远洋作战时所需的航空燃油按时补给问题,建立了带有自动调节系统的载机军舰航空燃油分段接力式补给的预测模型。对航空燃油分段接力式补给进行研究,采用系统动力学方法,构建影响补给船队补给效率的各元素因果回路图与存量流量图及预测模型,并以系统动力学软件Vensim PLE 5.9为平台进行建模仿真。运行结果表明,该模型在扰动条件下能进行航空燃油分段接力式补给趋势的预测,可为航空燃油分段接力式补给方案的制定提供理论依据。     

复合固体推进剂颗粒填充模型及其统计特性分析

复合固体推进剂属于高填充比颗粒类复合材料,氧化剂和金属颗粒在基体中的随机分布使其在细观尺度具有非均质的特点。从细观尺度研究固体推进剂燃烧及力学性能时,必须考虑颗粒级配、空间分布和种类等因素的影响。采用分子动力学方法,以硝酸酯增塑聚醚高能复合固体推进剂为研究对象,将固体颗粒模型化为球形,生成其在基体内随机分布的颗粒填充模型。利用Monte-Carlo算法模拟计算颗粒填充模型细观结构的两点概率函数,并研究了颗粒填充体积分数、尺寸与级配等参数对其的影响规律。从统计意义上给出具有各态历经性、统计均匀性和各向同性特点的颗粒填充构型最小周期性代表体元尺寸,可有效减小后续研究的计算量,节约计算成本。所构建的推进剂细观几何构型及对最小周期性代表体元尺寸的计算为后续开展复合固体推进剂细观尺度燃烧、燃面处铝团聚及力学性能数值研究奠定了基础。     

An efficient and modular modeling for launch dynamics of tubed rockets on a moving launcher

This paper develops a modular modeling and efficient formulation of launch dynamics with marching fire (LDMF) using a mixed formulation of the transfer matrix method for multibody systems (MSTMM) and Newton-Euler formulation. Taking a ground-borne multiple launch rocket systems (MLRS), the focus is on the launching subsystem comprising the rocket, flexible tube, and tube tail. The launching subsystem is treated as a coupled rigid-flexible multibody system, where the rocket and tube tail are treated as rigid bodies while the flexible tube as a beam with large motion. Firstly, the tube and tube tail can be elegantly handled by the MSTMM, a computationally efficient order-N formulation. Then, the equation of motion of the in-bore rocket with relative kinematics w.r.t. the tube using the Newton-Euler method is derived. Finally, the rocket, tube, and tube tail dynamics are coupled, yielding the equation of motion of the launching subsystem that can be regarded as a building block and further integrated with other subsystems. The deduced dynamics equation of the launching subsystem is not limited to ground-borne MLRS but also fits for tanks, self-propelled artilleries, and other air-borne and naval-borne weapons undergoing large motion. Numerical simulation results of LDMF are given and partially verified by the experiment.     

建立一类挠性航天器的动力学模型及面向控制的仿真环境

对于一类具有一个中心刚体和两块对称安装的太阳帆板的挠性航天器,针对其帆板较长、弹性位移较大,导致根据文献[2]直接建立的模型不准的问题,提出将弹性帆板分段处理的方法,分别引入浮动坐标系,建立系统的动力学仿真模型。并将针对整体模型设计的控制规律作用于该模型,进行了数值仿真。仿真结果表明,对于大变形情况,分段处理的方法十分有效。     

三组元液体火箭发动机实现单级入轨的优化分析

建立了三组元液体火箭发动机性能计算模型、单级入轨可重复使用运载器质量模型和弹道模型,以起飞质量为目标函数,优化得到了实现单级入轨的发动机基本参数。结果显示:三组元发动机性能比氢氧发动机高10%。本研究是三组元发动机系统设计和分析的基础。