鱼雷扩展螺旋机动搜索弹道设计

当不能准确掌握目标运动信息时,对鱼雷发射平台而言,目标位置散布于一定的区域之内。要提高鱼雷搜索捕捉目标的概率,可利用鱼雷航程远的特性,设计一种扩展螺旋机动搜索弹道,使鱼雷搜索范围尽可能地覆盖目标散布区域。基于这种设想,提出描述鱼雷扩展螺旋机动搜索弹道的参数和确定方法,并对这种弹道进行仿真和分析,得出其适用条件和不足之处。     

短波抗干扰方法实战性研究

在通信对抗中,短波抗干扰方法随着干扰方式和抗干扰技术的不断发展而变化,论文阐述了当前通用的干扰方式,通过机动野外实战对抗的方式对短波抗干扰方法进行深入研究,得出了部分阶段性理论成果.     

拖船回转机动状态下的拖缆暂态分析

拖船直拖到稳态定长回转过程中的拖缆暂态已有研究。对于大半径的拖船回转,Chapman大半径定长回转解法[1],假定拖体轨迹与拖体深度是单调指数关系。对于小半径的拖船回转,拖体的轨迹开始随着拖体深度的波动是一种螺旋线形状,最终趋于Chapman稳态回转值。本文通过定义了一个拖体深度与深度是单调与波动关系,提出了另一种确定Chapman理论大半径与小半径过渡值的方法。在考虑流的影响下的稳态定长回转时,没有求解稳态回转的方法。然而,拖体振幅是拖船回转半径和拖船速度的函数。依据稳态船体回转机动暂态分析来讨论单独360?和单独180?U型回转的动态特性,并得出一些有用的结论。对于某些回转半径而言,拖体所达到的深度比稳态回转所达到的深度大得多。对于180?回转半径小于拖缆长度的回转,拖体深度达不到稳态回转的深度。     

6种曲线元上的道路中桩坐标解算

当前线路平、纵、横设计要素面向的对象仍为为传统的施工测量手段，鉴于测量仪器及计算机的进步，设计要索的选择必须有利于快速、精确的获取施工放样数据。为建立统一数学模型，实现道路放样的数字化，避开了线路平面线形设计中常规组合方式，提出了曲线元的概念，统一概括为6种曲线元，通过坐标换算把曲线元上点位坐标统一到测量坐标系中。     

Three-dimensional analysis of transient slosh within a partly-filled tank equipped with baffles

The directional dynamic analyses of partly-filled tank vehicles have been limited to quasi-static fluid motion due to computational complexities associated with dynamic fluid slosh analyses. The dynamic fluid slosh causes significantly higher magnitudes of slosh forces and moments in the transient state that cannot be characterized through quasi-static approach, which provides reasonably good estimates of the mean responses. In this study, a three-dimensional nonlinear model of a partly-filled cylindrical tank with and without baffles is developed to investigate the significance of resulting destabilizing forces and moments caused by the transient fluid slosh, and the effects of baffles. The baffles and the end caps are modeled with curved shapes. The analyses are performed under varying magnitudes of steady lateral, longitudinal and combinations of lateral and longitudinal accelerations of the tank, and two different fill volumes using the FLUENT software. The results of the study are presented in terms of mean and peak slosh forces and moments, and variations in the mass moments of inertia of the fluid cargo within a clean bore and a baffled tank, for two different fill volumes and different magnitudes of acceleration excitations. The ratios of transient responses to the mean responses, termed as amplification factors, are further described to emphasize the significance of dynamic fluid slosh on the forces and moments induced on the vehicle. The results in general suggest that the mean responses attained from dynamic fluid slosh analyses correlate well with those attained from the quasi-static analyses for a clean bore tank. The amplification ratios of the resulting forces and moments could approach as high as 2. The results clearly show that the presence of baffles helps to suppress the peak as well as mean slosh forces and moments significantly.     

Three-dimensional analysis of transient slosh within a partly-filled tank equipped with baffles

The directional dynamic analyses of partly-filled tank vehicles have been limited to quasi-static fluid motion due to computational complexities associated with dynamic fluid slosh analyses. The dynamic fluid slosh causes significantly higher magnitudes of slosh forces and moments in the transient state that cannot be characterized through quasi-static approach, which provides reasonably good estimates of the mean responses. In this study, a three-dimensional nonlinear model of a partly-filled cylindrical tank with and without baffles is developed to investigate the significance of resulting destabilizing forces and moments caused by the transient fluid slosh, and the effects of baffles. The baffles and the end caps are modeled with curved shapes. The analyses are performed under varying magnitudes of steady lateral, longitudinal and combinations of lateral and longitudinal accelerations of the tank, and two different fill volumes using the FLUENT software. The results of the study are presented in terms of mean and peak slosh forces and moments, and variations in the mass moments of inertia of the fluid cargo within a clean bore and a baffled tank, for two different fill volumes and different magnitudes of acceleration excitations. The ratios of transient responses to the mean responses, termed as amplification factors, are further described to emphasize the significance of dynamic fluid slosh on the forces and moments induced on the vehicle. The results in general suggest that the mean responses attained from dynamic fluid slosh analyses correlate well with those attained from the quasi-static analyses for a clean bore tank. The amplification ratios of the resulting forces and moments could approach as high as 2. The results clearly show that the presence of baffles helps to suppress the peak as well as mean slosh forces and moments significantly.     

潜艇在海洋密度锋中受绕运动建模与仿真研究

根据分析潜艇通过海洋密度锋区的受力特点,建立潜艇在海洋密度锋中的受力和垂直面运动模型。通过潜艇垂直面运动仿真,分析自由运动、PID操舵控制、操舵加均衡控制和综合运用增速、操舵加均衡控制等情形下海洋密度锋对潜艇纵倾角、潜浮角和升沉运动的影响,结果表明综合运用操舵、增速和均衡进行控制可以更为有效地控制潜艇在海洋锋区航行深度和运动姿态。     

一种基于位置误差检测门限的机动目标跟踪算法

文章针对交互多模型算法（IMM）运算量大、模型集设定偏离真实目标机动轨迹等情况,通过将变结构交互多模型算法（VSMM）的机动检测准则进行改进,提出了一种基于位置误差检测门限的VSMM算法。通过将两种算法的跟踪效果进行仿真对比,结果说明文章所提算法能够较为有效地改善对机动目标的跟踪情况,具有一定的理论价值。     

试论单桨船制动机动中的偏向力

制动机动是船舶操纵运动中一个比较复杂而有重要实践意义的课题,舰船驾驶员必须充分掌握舰船的制动机动性能。但是,由于单螺旋桨舰船制动机动过程中的偏向力尚未得到充分的研究和论述,目前还不能完善地定性、定量分析单桨船制动机动中的复杂的偏转现象。本文在总结船模和实船试验的基础上,通过定性分析的方法,给出单桨船倒车偏向力的一般规律和水动力学解释,并给出几类单桨船制动机动偏向力的估算方法,有助于舰船驾驶员充分、快速地掌握本船的制动机动性能。