舰艇编队智能防空决策模型研究

海上战机稍纵即逝,指挥决策时间的长短往往可以决定小到1艘舰艇大到1支舰队的命运。在抗击来袭的空中目标问题上,已有的火力分配模型都存在一定的局限性,不能更好满足舰艇编队的防空需求。本文试图引入作为通用智能基础的Soar系统,对来袭的空中目标进行智能决策,建立舰艇编队智能防空决策模型。以Soar作为决策推理引擎,对所有来袭目标威胁程度不断循环推理,以期优化打击方案,大大降低决策时间,更好地满足实战需要,提高海上编队的防空作战能力。     

公路工程施工诱发滑坡的成因分析

在高速公路建设中常常会遇到各种不同类型的地质灾害,比如,滑坡、坍塌、路基病害、隧道病害、高边坡病害等等。有新产生的,也有因工程活动引发的,对不同性质的病害所采取治理的措施不尽相同。文中结合某在建高速公路中一处路堑边坡变形的产生与发展,谈了一些对“工程滑坡”肤浅的认识,供同行探讨。     

高校基建档案建设工作探析

论述了高校基建档案建设工作对高校发展的重要性,在指出当前高校基建档案建设工作中存在的基础上,最后提出了解决这些问题相应的措施,进一步分析了它的原因.     

Experimental and numerical study of the shielding effect of two tandem rough cylinders in flow-induce oscillation

The shielding effect of the downstream cylinder in flow induced oscillation (FIO) of two cylinders arranged in tandem is studied experimentally and numerically at Reynolds number 30,000 to 120,000. Both cylinders are in one degree-of-freedom, transverse-oscillations, and have turbulence stimulation in the form of selective surface roughness to expand FIO beyond vortex-induced vibration (VIV) into galloping. Shielding of the downstream cylinder has a negative effect on harnessing hydrokinetic energy. To study its effect and mechanics, selective cases are studied both numerically and experimentally and discussed to demonstrate the shielding effect on the downstream cylinder and understand its cause. The main conclusions are: (1) The shielding effect for the downstream cylinder shows a strong relation to the damping ratio. As the damping ratio increases, the shielding effect is mitigated. Additionally, the oscillation of the rear cylinder becomes stable and shows stable frequency. (2) In the VIV region, as the stiffness and natural frequency increase, the shielding effect decreases substantially. (3) In the VIV region, the vorticity of the vortices shedding from both the upper and the lower sides of the downstream cylinder does not accumulate enough due to the attraction by the vortices shed from the upstream cylinder, thus resulting in partial suppression of the oscillation on the downstream cylinder. (4) In the galloping region, the shielding effect for the downstream cylinder depends on whether the vorticity near the downstream cylinder is strengthened by the vortices generated by the shear layers of the upstream cylinder or weakened.     

Finite-time ship formation control based on extended state observer北大核心CSCD

[目的]为了解决大多数船舶编队控制算法控制周期长和时效性差的问题,提出一种基于扩张状态观测器(ESO)的有限时间控制策略。[方法]采用一种非线性终端滑模算法,通过对控制律分区域设计,克服传统终端滑模存在的奇异性问题;将非线性终端滑模与图论结合,实现有限时间的船舶编队控制;利用扩张状态观测器观测并补偿船舶模型中的不确定性及外界的干扰,以保证船舶编队控制的精确性;运用Lyapunov理论验证船舶编队控制律的稳定性。[结果]仿真结果表明,采用所提控制策略使整个编队系统误差在5 s左右趋近于0,从而实现了稳定。[结论]该控制策略能有效控制船舶编队,且控制速度快、时效性好。     

铝合金激光焊气孔数值模拟

采用透明玻璃观察激光焊过程的匙孔行为。基于菲涅耳吸收和多重反射方法,引入气泡模型,建立三维数值模型,研究铝合金激光焊中匙孔行为和匙孔型气孔的形成机理。结果表明:匙孔的形成与坍塌机理在数值模拟与试验中是相似的;匙孔前壁处的熔融金属沿前沿方向向下流动,而在匙孔后壁的熔池形成顺时针涡流;匙孔坍塌的主要步骤是匙孔后壁处形成凸起,匙孔后壁上的凸起继续向匙孔前壁处流动并与匙孔前壁接触形成液桥;气孔形成的主要因素是匙孔坍塌形成气泡和气泡被凝固界面捕获。     

基于编队海上列车概念的多艇编队航行水动力分析

以某型特种滑行艇为基础计算模型单元，基于编队海上列车概念，提出4种典型编队形式并进行计算流体动力学（Computational Fluid Dynamics，CFD）计算，探索多艇编队航行的减阻可行性，并开展多艇编队航行水动力分析，对指导海上多船编队航行具有一定的借鉴参考意义。     

顺直过渡段卵石浅滩形成条件分析

长江上游河段分布众多卵石浅滩,大多数属于碍航浅滩,通过对卵石浅滩形成条件的分析,深入了解浅滩的碍航成因,为航道整治提供一定的理论基础。基于对卵石浅滩成因与演变的分析,从泥沙起动机理和卵石浅滩形成的基础出发,导出了顺直过渡段卵石浅滩形成可能性的比降和河道宽深比的范围区间。利用大量的野外实测资料和试验资料进行验证,结果表明卵石浅滩形成是在一定的比降或河宽范围内的,同时提出了相对应的上下限表达式。