太平洋上的“宙斯盾”反导战舰群

2008年2月20日,美国海军部署在太平洋中部夏威夷海域的"伊利湖"号"宙斯盾"导弹巡洋舰在世人瞩目之下发射了一枚最新的"标准"-3型舰空导弹,随后"一弹中的",一举击毁了太平洋上空约247千米处一颗失控的间谍卫星。     

小型水下运载器快速上浮导弹发射过程扰动分析

区别于传统潜艇发射导弹，小型水下运载器由于尺寸小、重量轻、上浮速度快，导弹发射过程对其动力学特性具有重要影响。针对小型快速上浮运载器，对上浮过程、发射过程及开盖过程扰动进行建模，并对典型上浮发射导弹过程进行仿真分析。结果表明，开盖及发射过程对运载器弹道及姿态的扰动较小，而对上浮速度影响较大，发射后运载器控制效率显著下降。     

光彩夺目的“捕鲸叉”家族

“捕鲸叉”导弹是麦道公司(现被波音公司并购为美海军研制的全天候高亚音速中程多用途反舰导弹。1969年正式开展方案论证,并提出了用小型涡喷发动机推进的“捕鲸叉”中程导弹方案。首先提出的是打击大中型水面舰艇的空舰导弹发展计划,又于1971年在该计划中增加了发展舰射和潜射型导弹的内容。1972年10月20日,1架P-3C反潜巡逻机进行空射“捕鲸叉”导弹试射,成功命中靶舰,在其后几年的测试中,先后发射了350枚,命中率达93%。1978年6月,美海军接收第一批舰射型“捕鲸叉”导弹,空射型也于同年交货,而潜射型则在1981年才开始服役。1986年,美海军又提出使“捕鲸叉”导弹既可攻击水面舰艇,又可攻击陆上目标的要求,先后发展了“捕鲸叉”1B、1C、1D型和防空外空地导弹——“斯拉姆”(SLAM)。“捕鲸叉”导弹已经发     

非线性流函数在实验风浪场计算中的应用

风作用于水面产生风浪, 其中由于波流紊动产生的动量和能量的交换机制是一个很复杂的过程。风应力一般用来描述这种能量交换, 可以分为3个部分: 水面的剪切力、波生应力以及紊动应力。采用一种有效的非线性波流分离方法——NSFM(Nonlinear Stream Function Method)对波流运动的动量和能量输移进行定性描述。构造能够有效表达非线性波浪的解析流函数, 摄动求解使其满足拉普拉斯方程、动力边界条件和运动边界条件, 结合实验室风浪数据, 分离出波生速度场。通过交叉谱分析, 得到波生雷诺应力在不同风速下对风应力的贡献。结果表明: NSFM对不同工况条件下的风浪的处理具有较高的精度, 模型适应性良好; 且风速越大, 波生应力沿着水深衰减得越快, 且自由面波生应力在动量输移中的比重会逐渐减弱。     

1987年海洋石油勘探获得重大成果

中国目前规模最大的一座现代化军港,经过海军工程兵指战员连续11年苦战,现已基本完成港区建设,并开始进驻各类水面舰艇。这座军港总面积10.7平方公里,其中水域面积3.9平方公里,可同时驻泊数10艘导弹驱逐舰,并可快速获得油、水、电暖、弹等补给。这座综合性大型军港投入使用,使人民海军又增添了一个重要的水面舰艇基地,从而     

电磁发射深水炸弹空中弹道性能仿真分析

为了探讨电磁发射深水炸弹的弹道性能，采用六自由度刚体弹道模型和地面密集度仿真预测模型，研究了基于最大发射动能下电磁发射深弹的射程覆盖范围，计算了电磁发射深弹最大射程、最小射程下的落点误差，分析了各误差因素对电磁发射深弹射程、方向中间误差的影响情况。结果表明：1)电磁发射深弹的射程覆盖范围由发射装置最大发射动能和电磁发射深弹性能指标共同决定；2)电磁发射深弹的落点误差因素主要为初速误差、横向起始偏角误差以及风速误差。     

基于纵横波保幅分离的粘弹介质弹性波正演模拟

地下介质往往表现为粘弹特性,研究基于粘弹假设的数值模拟方法对于正确认识地震波的传播规律和提高地震勘探精度具有重要意义。波动方程正演过程中纵横波的保幅解耦是研究准确的粘弹介质中地震波传播机理的前提,基于散度和旋度算子的纵横波解耦方法会使波场的相位和振幅产生畸变,且解耦后的波场在极性反转位置上无法与分离前混合波场各分量对应。在散度和旋度算子上再做一次梯度和旋度运算的波场分离方法虽然能够克服上述缺陷,但存在保幅性差等问题。本文从粘弹介质中的一阶速度-应力方程出发,推导了矢量纵横波分离的波数域表达式,结合有限差分思路给出了其在空间域的求解方法。本文方法利用纵横波的传播速度对现有的矢量波场分离方法进行振幅校正,并将校正结果分别作为纵波与横波对时间的二阶偏导,实现了粘弹介质中的纵横波分离。模型试算结果表明,本文方法能够克服现有方法的缺陷,获得更具保幅性的波场分离结果。     

磨刀霍霍的日本海上自卫队

开动世界上最先进的雷达系统,出动世界上最先进的水面舰艇、飞机和全副武装的陆上自卫队员——这是日本于今年初进行的大规模模拟军事演习的场面。1998年,朝鲜越过日本北部向太平洋发射了一枚“大浦洞---2”导弹,于是日本借机无限夸大威胁,增拨军费从美国购组件装备间谍卫星和世界上最先进的 THAAD 雷达,使日本的雷达监视能力达到俄罗斯和中国国土     

深水炸弹垂直发射技术初探

回顾深水炸弹发展的历史进程，分析未来海战所面临的作战任务对深水炸弹武器系统的需求，阐明了深水炸弹在未来战争中不可或缺的地位。 通过梳理传统深弹发射方式，提出了深弹垂直发射所要解决的箱式发射技术以及深弹垂直“冷”、“热” 发射方案。     

海浪对水下垂直运动航行体出水姿态的影响分析

水下弹道是潜艇垂直发射导弹特有的一段弹道,导弹在航行过程中受到表层海水自然流动的影响,运动姿态发生复杂变化,其中,以海浪的影响最为明显。根据二维线性波理论在发射坐标系下建立了波浪模型,通过莫里森方程分析了海浪对水下垂直运动导弹的作用形式,建立了导弹水中运动数学模型,借助有限元思想,在Matlab/Simulink环境下仿真分析了不同航向和浪级下导弹水中运动姿态的变化规律,结论可为研究潜射导弹水中弹道提供参考和依据。     

基于排队论的水下预置反舰导弹部署优化

随着武器装备的逐渐智能化和信息化，武器系统的水下预置已经成为了未来水下无人作战体系中的重要研究内容之一。以封锁作战为背景，用水下预置反舰导弹构建多层防御阵线封锁战略航道，对敌实施打击。利用排队论相关理论研究了水下预置反舰导弹对来袭舰船编队总的命中概率并建立了其线形部署优化模型。通过仿真算例验证了模型的有效性，分析了影响优化结果的其他因素，结果表明：该模型能够准确找出在总命中概率最大时最佳的部署层数和各层部署数量，可为水下预置反舰导弹的部署决策提供一定科学参考。     

Intensification of nonlinear wind waves on clean water and in the presence of an oil film

The intensification of gentle plane waves at the initial stage of their generation by a steady wind flow in a laboratory setup is investigated. It is found that the wave form is changed by eddies that are formed in the viscous layer of a steady air flow on the leeward slope: the water surface rises under the action of eddies to form a complexly shaped slope. Calculated and measured data for gentle nonlinear waves on clean water are in good compliance with each other. It is shown that, in the presence of an oil film, the region of eddy separation encompasses the wave trough as well, because oil flows down and the film is thickened in passing from the slope to the trough. The water-surface rise by eddies in the trough restricts an increase in the amplitude and steepness of the wave.     

Study on the gas-curtain generation characteristics by the multiple gas jets in a liquid-filled tube

To further understand the gas-curtain generation characteristics during the launching process of the underwater guns, a simulated gas-injector with multiple nozzles is designed and the expansion process of these multiple combustion-gas jets is experimentally captured. Experiment results indicate that, with turbulent mixing between the gas jets and the liquid medium, the gas curtain is generated in the observation chamber. Based on the experiment, a three dimensional unsteady model is established to simulate the expansion process of the multiple jets. Numerical result shows, with the injection of the gas jets, pressure declines in the Taylor cavity along the axial direction at the beginning. During the expansion process, the multiple jets contact and interact with each other, and pressure rises in the mixing area. After merging, backflow vortexes interact and converge, and the vortexes move along the axial direction with the expansion of the combustion gas jets.     

Concept analysis and laboratory observations on a water piercing missile launcher

The water piercing missile launcher (WPML) is a new concept for launching missiles from submerged platforms. The WPML employs a high speed gas jet, using rocket exhaust as the gas source, to create a dry path underwater through which a missile may pass without contacting water. The gas jet is deflected due to cross flow and the gas jet trajectory is computed through a semi-empirical relationship commonly used to describe single phase jet deflection. This relationship, which requires an experimentally determined constant to predict jet deflection, is computed using experimental data. Uncoupled simulations of rocket exhaust and missile dynamics are shown to demonstrate how such a launcher could be utilized in launching a generic artillery missile. Although the results indicate the optimal launch depth, in terms of maximizing the launch depth while minimizing missile restraint time, is 14 m given an 8 m/s submarine speed it may be possible to launch a missile from a moving submarine at a speed of 5 m/s at a maximum depth of 20 m.     

基于MODIS数据的渤海海冰厚度反演算法优化

海冰厚度是监测与研究渤海海冰的重要参数。为了获取更加可靠的渤海海冰厚度数据,本研究基于MODIS数据对海冰厚度反演中的冰水分离环节和冰厚计算方法都进行了改进。对于冰水分离环节,本文在Canny边缘检测算子提取海冰基础上,加入了二值化处理、阈值判别等步骤,实现了较高精度的渤海海冰范围自动化提取。通过试验确定了海冰厚度与反照率指数关系模型中的参数,包括海冰衰减系数和海水反照率参数,使其更加符合渤海海区的物理特征。将改进后算法的海冰厚度反演结果与渤海海上石油平台实测数据进行比较,并分析了误差来源。结果表明,经过对算法的改进,海冰厚度与反照率指数关系模型的反演结果与实测数据之间的平均绝对误差由7.05 cm缩小到2.74 cm,相关系数由0.434提高到0.485。     

Parametric study on offshore jacket launching

Platform structures are commonly utilized for various purposes including offshore drilling, processing and support of offshore operations. Jacket type structures are attractive in relatively shallow water regions. A jacket is a supporting structure for deck facilities stabilized by leg piles through the seabed. The size of a jacket is dependent on deck size, pile dimensions and environmental loads. In a jacket design, operational and environmental loads are very important and must be investigated intensively to secure the stability of structures during their operation life, and installation phase as well. To confirm the stability, several analyses including in-place, fatigue, dynamic, load-out, transportation, lifting, and launching are performed. As the jacket weight and dimensions become large, a launching technique is applied to install the jacket. The launching analysis needs to consider quite a number of parameters including environmental conditions, launch barge specification, ballast, trim angle, local member integrity, etc. Due to the complexity of the operation, there is not a straightforward guideline or procedure for analysis. In this paper, a general procedure for analysis with various conditions and launching criteria are discussed and investigated. The effects of parameters are closely examined by numerical modeling.     

靠球减震系统在导管架平台中的应用

导管架生产储油平台在油轮靠泊和外输期间,如遇风浪天气,平台的晃动非常明显,为此引入橡胶靠球减震系统。运用ANSYS有限元分析软件,建立导管架生产储油平台的真实有限元模型,计算平台在靠船碰撞力和波浪力共同作用下平台关键点位置应力变化及振动响应过程,为靠球减震系统在实际工程中应用提供理论依据。     

Distortion of thin shells due to rapid temperature changes

A mathematical model which predicts pressure changes and resultant hull distortion due to variations in temperature of a thin closed shell is presented. The model is of general application but in this paper it is specifically applied to the case of a small sailing boat whose bouyancy depends on the fact that the hull is effectively a water-tight shell made of GRP. In extreme climates such as vessel experiences large temperature changes on launching and beaching and pressure differentials of the order of 2 psi can result. The design of the hull incorporates a small vent hole to relieve the pressure build-ups but the recommended diameter is shown to be too small to avoid damage. Reasons for structural failures, which have frequently been observed, are presented.     

浮筒辅助大型导管架结构整体拆除上浮过程动力响应特征研究

浮筒辅助大型导管架结构整体拆除作业是一个连续过程,作业过程中拆除系统的动力荷载及动力参数均会发生显著变化,传统基于某一稳定状态的结构动力响应分析方法不能准确预测拆除系统上浮过程中的动力响应。通过建立浮筒辅助大型导管架结构整体拆除上浮过程动态分析模型,对拆除系统上浮过程的动力响应特性进行研究。结果表明,整体拆除动态分析模型可以准确描述拆除系统上浮过程中浮筒及导管架浮力变化对上浮高度的影响机制,拆除系统上浮高度约为不考虑浮筒和导管架浮力变化时的90%。此外,浮筒辅助大型导管架整体拆除方法的动态稳定性较强,四级海况下拆除系统的最大偏移量仅为4.2 m,有较好的工程应用前景。