Shock wave mitigation using zig-zag structures and cylindrical obstructions

The present study focuses on the mitigation of shock wave using novel geometric passages in the flow field. The strategy is to produce multiple shock reflections and diffractions in the passage with minimum flow obstruction, which in turn is expected to reduce the shock wave strength at the target location. In the present study the interaction of a plane shock front (generated from a shock tube) with various geometric designs such as, 1) zig-zag geometric passage, 2) staggered cylindrical obstructions and 3) zig-zag passage with cylindrical obstructions have been investigated using computational technique. It is seen from the numerical simulation that, among the various designs, the maximum shock attenuation is produced by the zig-zag passage with cylindrical obstructions which is then followed by zig-zag passage and staggered cylindrical obstructions. A comprehensive investigation on the shock wave reflection and diffraction phenomena happening in the proposed complex passages have also been carried out. In the new zig-zag design, the initial shock wave undergoes shock wave reflection and diffraction process which swaps alternatively as the shock front moves from one turn to the other turn. This cyclic shock reflection and diffraction process helps in diffusing the shock wave energy with practically no obstruction to the flow field. It is found that by combining the shock attenuation ability of zig-zag passage (using shock reflection and diffraction) with the shock attenuation ability of cylindrical blocks (by flow obstruction), a drastic attenuation in shock strength can be achieved with moderate level of flow blocking.     

2011年度美国参谋长联席会议主席指南

美国参谋长联席会议主席指南是指导联合参谋部工作和联合部队建设的年度文件.2011年度指南提出的优先任务与战略目标有3个:在大中东和中南亚捍卫美国的重要国家利益,改善部队的健康问题,平衡全球战略风险.指南还提出确保联合部队执行新的、废止"不问,不说"的政策,确保整个废止过程有序引导,保持部队的战备.     

锻造海军陆战队特种作战勇士

美国海军陆战队特种作战司令部成立四年以来,能力逐日增强,作战任务多样而繁复,为了应对不断增加的作战需求,司令部对内部结构和规模着手进行调整,单位编组、人员选拔、课程训练等各方面都提出了相应计划,以期用最优状态打赢未来战争.     

俄罗斯19～20世纪战争的结论和启示

在19~20世纪的俄(苏)历史上,发生了包括两次世界大战在内的多场战争,每一场战争,俄国均有失误和错误.本文从分析这些战争的基本结论和教训入手,提出了现代条件下如何进行军事建设的一些思考.