水下发射超空泡射弹对UUV平台姿态影响分析

超空泡射弹武器能够突破普通射弹水中运动极限，有效打击水雷等水下目标。针对水下发射超空泡射弹武器的平台适应性开展了初步研究，建立了超空泡射弹武器及 UUV 搭载平台仿真模型，计算分析了水下超空泡射弹武器在不同方位、不同角度发射时 UUV 平台姿态角的变化，得到了水下发射超空泡射弹对 UUV 平台姿态的影响规律，为水下超空泡射弹武器系统及其平台适配性研究提供了依据。     

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。     

连续冲击条件下水下潜器运动姿态估计方法

基于潜器水下状态的平衡方程,建立了潜器运动模型.通过对水锤压力的数值仿真计算,建立了潜器航行体发射时的运动控制模型.根据这一数学模型,计算分析了潜器在完整火箭发射后效(发射冲击与完整的水锤效应)作用下的运动响应和运动控制.结果表明:发射单枚航行体对潜器运动姿态有较长时间的影响,潜器的初始速度越大,影响程度越小,影响时间...     

一种发射平台水面多弹分离过程的运动特性分析

水下运载器携带载荷至水面并快速完成分离是该类武器应用的重要环节。 以发射平台水面逐一发射多枚导弹的技术方案为背景,利用多刚体动力学模型对动基平台的水面多弹分离过程进行了数学建模。 在方案初步设计阶段,将三维模型进一步简化为一维模型,编写了可实现任意装填枚数的动基平台水面多弹分离过程动力学仿真软件;分析了平台出水速度、导弹装填枚数以及导弹发射间隔等参数对分离过程运动特性的影响;得到了发射平台水面发射多枚导弹的弹道变化规律。 计算结果具有一定的工程应用参考价值。     

基于接触式扫雷的水下聚能剪切内弹道研究

以陆地枪械发射内弹道方程组理论为基础,结合水下聚能剪切器动作的技术特点,对动刀运动的能量转化机理和刀架内部组件的动力学响应进行了综合分析,建立归一化数学模型,用于内弹道参量变化特性曲线的数值计算。通过对某型号水下剪切器内弹道仿真求解,定量分析了各参量变化过程,论证了短行程聚能剪切方案的可行性,为后继内弹道设计及装药参量的优化奠定了理论基础。     

海浪对水下电磁场幅值影响的分析

讨论了海浪波动基本规律,分析了海浪波动对水下接收点电磁场幅值的影响。理论计算表明,这种影响取决于海浪的有效波高和电波穿透深度的比值。在近似正态分布的海浪作用下,水下场强幅值呈现出对数正态分布的规律。海浪波动会造成场强均值增加和场强幅值波动。海浪对场强幅值的影响随着电磁场频率的下降显著地降低。     

大深度水下滑翔机总体设计

水下滑翔机(Autonomous Underwater Glider，AUG)是一种浮力驱动的自主水下航行器 (Autonomous Underwater Vehicle，AUV)，通过调整滑动质量块来改变重心与浮心的相对位置，从而控制自身的运动姿态。完成了水下滑翔机的外形设计，同时，对其各系统组成部分进行了初步设计与布局。利用 MATLAB 软件基于计算得到的流体动力参数对滑翔机进行运动特性分析，得出定常运动状态下攻角、俯仰角和水平速度等参量随重心水平位移和净浮质量之间的关系。最后使用 Simulink 软件对垂直面内滑翔机的运动模型进行弹道仿真，验证了水下滑翔机总体设计方法的有效性和可行性。     

高海况下无人水下航行器的横摇运动分析

为明确高海况下海况等级对无人水下航行器横摇运动的影响,得出满足某型无人水下航行器安全回收的海况条件,对高海况下无人水下航行器的横摇运动进行分析。运用频率响应法,分别在4级、5级和6级海况下，根据海浪谱密度函数和该型航行器的横摇频率响应函数,求得其横摇运动谱密度函数。再运用公式推导,得到其横摇运动的时域函数。使用MATLAB仿真软件对该型航行器进行横摇运动仿真,得到3种海况条件下，其横摇运动的时域函数图像,并验证仿真结果的准确性。仿真结论:高海况下的海况等级对无人水下航行器的横摇幅度有较大影响,满足其安全回收的海况条件为5级海况。     

XBT探头外形数值模拟及实验研究

XBT探头是一种手持投弃式温深剖面测量探头,外形结构直接影响其在水中的运动姿态,进而影响其采集数据的准确性。采用N-S方程及k-ε湍流模型对三种不同外形XBT探头的压力场和速度场进行数值模拟,研究了在不同雷诺数下阻力系数的变化趋势,获得了三种不同外形XBT探头的运动极限速度。通过分析攻角与升力关系表明有尾翼探头能够获得稳定的垂直下落姿态。由数值模拟分析结果与实验结果对比可知极限速度基本相符,验证了该数值模拟方法的正确性,可为XBT探头的结构设计提供重要的理论依据。     

水下运动物体及海底地形的SAR探测的初步研究(一)水下运动物体的SAR仿真影像分析

当物体在水中运动时,它所引起的流场变化会调制海水表面的小尺度波动,从而可以被合成孔径雷达（ＳＡＲ）所探测。本文建立了一个三维半隐式格式,对水下运动物体的绕流问题进行了数值计算。在袁业立有关海波高谱形式及ＳＡＲ影像原理的理论分析基础上,本文进一步计算了水下运动物体ＳＡＲ影像的Ｇ值分布图,并讨论了物体深度、海水水深、海表面主波方向对水下运动物体ＳＡＲ影像的影响。     

Wave effects on ascending and descending motions of the autonomous underwater vehicle

In the paper, a hydrodynamic model including the characteristics of maneuvering and seakeeping is developed to simulate the six-degree of freedom motions of the underwater vehicle steering near the sea surface. The corresponding wave exciting forces on the underwater vehicle moving in waves are calculated by the strip theory, which is based on the source distribution method. With the hydrodynamic coefficients relevant to the maneuvering and seakeeping, the fourth-order Runge–Kutta numerical method is adopted to solve the equations of motions and six-degrees of freedom of the motions for the underwater vehicle steering near the free surface can be obtained. The wave effect on the corresponding motions of the underwater vehicle is investigated and some interesting phenomena with respect to different wave frequencies and headings are observed. The hydrodynamic numerical model developed here can be served as a valuable tool for analyzing the ascending and descending behaviors of the underwater vehicle near the sea surface.     

复杂海况下水下拖缆数值分析研究

为了解复杂海况下风浪对水下拖缆的影响进行了动力学仿真研究。以P-M谱作为海浪谱密度公式,计算一组不同频率的组成波,采用线性波浪叠加法,计算由波浪引起的空间流场速度及加速度,推导叠加波的干扰力,将不规则波引入水下拖缆动力学模型中,采用四阶龙格库塔积分法对动力学模型进行数值求解,讨论拖缆在不同海况下的动力特性。结果表明,随着海况等级的提高,叠加波的频率范围逐渐降低,拖缆的垂向偏移量以及拖点处张力均会产生明显增加及波动,且其波动周期接近叠加波的平均周期;在不同浪向角的作用下,拖缆波动规律与规则波作用下类似,但也具有一些不规则波的特点。     

“世越号”沉船打捞中综合海洋测绘技术的应用

韩国"世越号"沉船打捞于2015年8月开展,打捞方案的制定和实施均需要海洋测绘技术的支持,尤其是水下穿钢梁施工,对水下定位精度要求极高。详细介绍了整个打捞施工过程中应用的海洋测绘技术,主要包括沉船水下三维姿态探测、沉船周边地形地貌地质调查、海洋环境监测、水上水下导航定位以及沉船起浮姿态监测等。通过一系列的技术创新,促进了打捞施工的顺利进行,为"世越号"打捞出水提供了重要的技术保证,开创了综合海洋测绘技术在重大救助打捞领域的系统作业模式。     

基于模糊神经网络理论对水下拖曳体进行深度轨迹控制

以华南理工大学开发的自主稳定可控制水下拖曳体为研究对象,首先通过水下拖曳体在拖曳水池样机中的试验取得试验数据后作为训练样本,采用LM BP算法,建立基于神经网络理论构建的可控制水下拖曳体轨迹与姿态水动力的数值模型。在此基础上设计了一个控制系统,它主要由两部分组成:基于遗传算法的神经网络辨识器和基于模拟退火改进的遗传算法的模糊神经网络控制器。以满足预先设定的拖曳体水下监测轨迹要求为控制依据,由控制系统确定为达到所要求的运动轨迹而应采用的迫沉水翼转角,以此作为输入参数,通过LM BP神经网络模型的模拟计算预报在这一操纵动作控制下的拖曳体所表现的轨迹与姿态特征。数值模拟计算结果表明:该系统的设计达到了所要求的目的;借助这一系统,可以有效地实现对拖曳体的深度轨迹控制。     

Experimental study of the hydrodynamic performance of an onshore wave power device in the presence of an underwater mound

The hydrodynamic functioning of an oscillating water column (OWC) in the presence of an underwater tri-dimensional mound (UTDM) through large-scale ocean engineering basin experiments is described. Experiments are carried out with both regular and irregular waves and are compared to numerical models. The analysis is based on the measurements of the wave amplification in the water column for the OWC performance and on surface deformation upwave and over the UTDM for the wave transformation due to both UTDM and OWC. A significant increase of the capture-width ratio due to wave focusing above the mound is observed experimentally. This wave focusing is also well described numerically with a refraction–diffraction model. The wave amplification in the water column for both regular and irregular waves is compared to results from a linear potential model based on an integral matching method. Linear behaviour of the hydrodynamic response of the device is verified for both open and partially closed conditions, in particular for irregular waves.     

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.     

提高水下GPS定位精度方法研究

水下GPS定位是近几年发展起来的高新技术.承载GPS接收机的海上浮标由于受海浪的影响,使得GPS接收信号附加了海浪信息,最终影响到水下目标的精确定位.针对海浪影响水下GPS定位精度现状,提出基于样条函数的数据分频处理方法,从而有效地分离海浪引起的长周期性漂移误差和短周期性随机误差,提高水下GPS定位精度.通过对实测数据的处理,证明了该方法的有效性.     

南海北部陆坡海区春末第一模态内孤立波观测及特征分析

为获取南海北部陆坡海区第一模态内孤立波的动力结构及时间变化特征,本文利用该海区1套内孤立波浮标观测数据,对陆坡海区的内孤立波现场观测数据分析,识别判定了2021年5月5日至6月3日共30 d的179次第1模态内孤立波过程,并进行了内孤立波的特征分析。南海北部陆坡海区第1模态内孤立波剖面流场为双层结构,上层主要为西偏北向流动,下层流向与之相背,流速转向发生在100～150 m深度处。内孤立波期间,最大流速多发生于上层,流速为60～120 cm/s,底层流增强,上层流与下层流流向相反。受内潮影响,研究区域内孤立波存在半日和全日2个周期,主要以20～30 min间隔的波列形式向西偏北方向传播。本文关于南海北部陆坡海区第一模态内孤立波的分析研究有助于提升对该海区内孤立波时空变化特征的认识,为工程水下施工提供参考和依据。     

Effect of wave action of a two-layer flow on underwater obstacles

A force action caused by the generation of internal waves in the vicinity of a density jump layer in a marine medium and exerted on underwater obstacles streamlined by a two-layer flow has been studied as part of a theoretical model. A horizontal element of an engineering structure, for example, a transport pipeline, which is modeled by a point dipole, is selected as an underwater obstacle. The integral representations for the wave resistance and the lift force are obtained. The characteristic features of variation in the hydrodynamic reactions to the streamlined obstacle, as well as the conditions of their significant intensification are revealed.     

On the modeling of wave propagation on non-uniform currents and depth

By transforming two different time-dependent hyperbolic mild slope equations with dissipation term for wave propagation on non-uniform currents into wave-action conservation equation and eikonal equation, respectively, shown are the different effects of dissipation term on the eikonal equation in the two different mild slope equations. The performances of intrinsic frequency and wave number are also discussed. Thus the suitable mathematical model is chosen in which the wave number vector and intrinsic frequency are expressed both more rigorously and completely. By using the perturbation method, an extended evolution equation, which is of time-dependent parabolic type, is developed from the time-dependent hyperbolic mild slope equation which exists in the suitable mathematical model, and solved by using the alternating direction implicit (ADI) method. Presented is the numerical model for wave propagation and transformation on non-uniform currents in water of slowly varying topography. From the comparisons of the numerical solutions with the theoretical solutions of two examples of wave propagation, respectively, the results show that the numerical solutions are in good agreement with the exact ones. Calculating the interactions between incident wave and current on a sloping beach [Arthur, R.S., 1950. Refraction of shallow water waves. The combined effects of currents and underwater topography. EOS Transactions, August 31, 549–552], the differences of wave number vector between refraction and combined refraction–diffraction of waves are discussed quantitatively, while the effects of different methods of calculating wave number vector on numerical results are shown.