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装甲师火力联合能力是一个复杂的多指标综合体系,通过建立装甲师火力联合能力评估模型,确定评估指标,运用云重心理论对其进行探索。在对云重心理论介绍的同时详细地给出了其实现步骤,最后用加权偏离度(θ)来衡量火力联合能力与理想状态的偏离程度,以确定装甲师火力联合能力的优良,并结合算例验证此方法的实用性和有效性,增强模型的可信度和可操作性。对装甲师火力联合能力的评估提供了有效的方法和途径。 相似文献
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本文运用误差理论分析了在海上用六分仪观测天体高度时由于六分仪倾斜或天体反射影象偏离望远镜视野中央以及由于船摇摆使眼高变化而引起的观测高度的误差,并提出了减小这些误差的建议。 相似文献
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重力相似偏离是河工模型试验中常用的技术手段。本文利用建立的推移质运动平面二维水沙数学模型研究此问题。设计一个转折角为30°的弯道动床概化模型,设置不同种类的底沙,允许重力相似有所偏离,研究不同重力相似偏离程度下河床的冲淤分布。通过分析泥沙的变化,参照规范得到了重力相似偏离的适用范围。 相似文献
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利用云重心理论构建炮兵群(团)生存能力评估模型步骤为:确定评估对象指标体系、计算指标权重、列出指标的状态值、确定云的重心向量及确定加权偏离度,并通过实例验证了该模型的可行性。此方法简单易行,可操作性强,为炮兵群(团)生存能力评估提供了有效的方法。 相似文献
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船舶航行条件经常变化,使主机和螺旋桨偏离设计的匹配工作点,从而导致机桨技术经济性能下降,在某些情况下,所谓的设计工况徒有虚名。本文分析了上述情况产生的原因,提出了解决这些问题的方法,并试图用最优化理论处理这些问题,从而将主机与螺旋桨匹配点的选择建立在最优化计算的基础上。 相似文献
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针对GPS导航仪的船位偏离航线指示,与海图上的船位偏离航线情况发生不一致现象,笔者提出了改进绘制航线的方法,避免这种现象发生的措施和一旦发生后的解决办法,供大家使用GPS导航仪时参考。 相似文献
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This study presents a numerical method for optimizing hull form in calm water with respect to total drag which contains a viscous drag and a wave drag. The ITTC 1957 model-ship correlation line was used to predict frictional drag and the corrected linearized thin-ship theory was employed to estimate the wave drag. The evolution strategy (ES) which is a member of the evolutionary algorithms (EAs) family obtains an optimum hull form by considering some design constraints. Standard Wigley hull is considered as an initial hull in optimization procedures for two test cases and new hull forms were achieved at Froude numbers 0.24, 0.316 and 0.408. In one case the ES technique was ran for the initial hull form, where the main dimensions were fixed and the only variables were the hull offsets. In the other case in addition to hull offsets, the main dimensions were considered as variables that are optimized simultaneously. The numerical results of optimization procedure demonstrate that the optimized hull forms yield a reduction in total drag. 相似文献
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CFD敞水螺旋桨性能计算分析 总被引:2,自引:0,他引:2
根据螺旋桨的投影原理及其型值参数,建立螺旋桨的三维模型。基于计算流体动力学(CFD)理论和CFD商业软件进行研究,采用分区混合网格方案和动网格技术及旋转坐标(MRF)方法,结合RANS方程和RNG湍流模型对螺旋桨三维粘性流动进行数值模拟,得到该螺旋桨的推力及其转矩。经与试验结果比较分析,证实该方法能实现对螺旋桨的敞水粘性流场模拟,预报其敞水性能。 相似文献
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This paper treats ground faults in mixed DC and AC systems. Grounding methods affect common-mode voltage and circulating currents under normal conditions. Ground faults produce fault currents and systemwide offsets throughout the system with respect to ground. During ground fault transients, the aggregate bus-to-ground ground capacitance and inductance produce underdamped oscillatory overvoltages. Continuous operation under DC or AC offset affects component selection. 相似文献
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在Excel中编程实现了导管空气螺旋桨的性能计算,使得计算过程更加直观可视,并将计算结果较快转化形成导管桨性能计算书中的表格形式。在AutoCAD中编制了LISP程序,利用Excel中生成的剖面型值,较为方便的绘制桨叶图,并自动加密剖面轮廓线控制点以形成CATIA中建模所需数据文件。在CATIA中通过二次开发,实现了桨叶三维模型的自动绘制,该模型不仅可用于整艇的三维建模,亦可用作CFD计算的输入模型。对设计过的气垫船导管空气螺旋桨进行汇总,形成了设计数据库。 相似文献
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Catenary risers have an interaction zone with the seabed, usually referenced as flowline. Movements in this region can be induced by sea currents and large offsets in floating unit, leading to touchdown position changes and affecting internal loads along riser length. In this work the contact flowline-seabed is modeled including sliding and rolling friction. Case studies involving large offsets in floating unit and lateral sea currents are solved to better understand the consequences of possible rolling and large sliding. The riser is modeled using a geometrically-exact finite element beam model. The contact is addressed with a new technique to include rotation movements from underlying beam models. This leads to global riser models including complex kinematics, being able to represent scenarios with alternating sliding/rolling and its consequences on internal loads of riser structure. A parametric study is performed to measure the influence of the friction coefficient in tension and torsion along typical flexible pipe and steel pipe catenary risers. 相似文献
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输送带跑偏危害大,由设计缺陷和安装误差引起的跑偏最难处理.笔者结合实践经验,着重从使用管理的角度,分析、说明几种跑偏故障的原因和处理方法. 相似文献