The Deep Impact Earth-Based Campaign

Prior to the selection of the comet 9P/Tempel 1 as the Deep Impact mission target, the comet was not well observed. From 1999 through the present there has been an intensive world-wide observing campaign designed to obtain mission critical information about the target nucleus, including the nucleus size, albedo, rotation rate, rotation state, phase function, and the development of the dust and gas coma. The specific observing schemes used to obtain this information and the resources needed are presented here. The Deep Impact mission is unique in that part of the mission observations will rely on an Earth-based (ground and orbital) suite of complementary observations of the comet just prior to impact and in the weeks following. While the impact should result in new cometary activity, the actual physical outcome is uncertain, and the Earth-based observations must allow for a wide range of post-impact phenomena. A world-wide coordinated effort for these observations is described.     

复合材料飞机结构损伤容限和耐久性设计初探

虽然军机和民机规范对复合材料结构的损伤容限和耐久性均提出了要求,但迄今为止尚无成熟的设计方法可用。本文试图通过对国外经验的归纳总结,并结合自己的研究成果,提出一种切实可行的方法供参考。限于篇幅,本文仅就加筋结构蒙皮遇到的几个问题进行讨论。     

Foreign Object Damage to Fan Rotor Blades of Aeroengine Part I： Experimental Study of Bird Impact

The conditions of experiment for bird impact to blades have been improved. The experiment of bird impact to the fan rotor blades of an aeroengine is carried out. Through analyzing the transient state response of blades impacted by bird and the change of blade profile before and after the impact, the anti-bird impact performance of blades in the first fan rotor is verified. The basis of anti-foreign object damage design for the fan rotor blades of an aeroengine is provided.     

飞机圆弧风挡鸟撞动响应研究

 以全尺寸鸟撞模拟试验测试的撞击力、位移、应变、应变率等参数为基础,研究了圆弧风挡的鸟撞动响应问题对鸟撞问题的性质、载荷计算方法及分析方法等进行了探讨,得出了一些有益的结论。     

水下爆轰燃气泡形态与激波传播过程研究*(爆震专刊)

针对脉冲爆轰发动机在水下工作过程中形成的燃气射流问题,搭建了水下爆轰燃气实验系统,研究了第一个爆轰循环在水下的燃气泡发展变化过程。建立了基于气液两相双流体模型的脉冲爆轰发动机水下喷射模型,采用时-空守恒元和求解元方法,模拟了爆轰波退化为激波在水中的传播及衰减过程。研究结果表明：燃气泡前期受外界水环境阻滞作用呈现“豌豆状”形态,充分发展阶段气液交界面逐渐失稳,在达到最大尺寸后开始收缩并在中心轴线位置出现凸出的射流；水下爆轰燃气射流发展过程中同时存在脱离燃气泡的水中前导激波和管口燃气泡内的高压区两部分,水中前导激波在传播过程中压力迅速衰减至常压量级,而管口燃气泡内则一直保持较高压力；中心轴线区域气液交界面处反射激波的回传使管口附近出现回击现象,并导致前导激波波阵面上压力峰值逐渐出现在30°方向上。     

大型水陆两栖飞机吹气襟翼设计与分析验证

针对大型水陆两栖飞机的使用特点和指标要求,以原型机翼为基础,重点开展机翼附面层控制增升装置设计技术研究,设计了附面层控制的吹气襟翼方案.采用计算流体动力学方法作为初步设计的评估手段,全面分析评估了设计方案的气动力特性和流场结构,最后通过风洞试验验证了该方案的增升效果.结果显示该设计方案在较宽的吹气动量系数范围内,最大升力系数均有不同程度的增幅,在吹气动量系数约为0.2左右时,获得最大的升力系数增量约为1.0,按照原型机的滑流影响规律推算,当采用吹气襟翼的主动流动控制方案后,起降速度能下降约30%,达到了设计指标.      

射流孔交错偏置排布下的楔形凹表面对流换热数值研究

通过三维数值模拟的方法研究了射流孔交错偏置排布下的楔形凹表面对流换热,在射流孔偏置间距比（L/d）为0~2.5、射流孔距凹腔前缘间距比（H/d）为6~12、射流冲击雷诺数（Re）为10000~28000的研究参数下,研究结果表明射流孔交错偏置排布在凹腔中诱导复杂的涡流,对应于射流冲击驻点区的局部表面传热系数得到增强;相对于直线排布的射流孔,小射流孔交错偏距比能够使得凹腔前缘附近沿弦向的展向平均努塞尔数相对射流孔直线排布方式有所改善,随着射流孔交错偏距比增加,沿弦向的展向平均努塞尔数最大值所对应的弦向位置逐渐向凹腔前缘下游迁移.为了在保持凹腔前缘对流换热能力不受到显著削弱的前提下,改善凹腔前缘附近的射流冲击对流换热能力,射流孔交错偏距比宜选择在1倍射流孔直径左右.      

Experimental investigations for parametric effects of dual synthetic jets on delaying stall of a thick airfoil

A promising strategy of synthetic jet arrays(SJA) control for NACA0021 airfoil in preventing flow separation and delaying stall is investigated. Through aerodynamic forces, flowfield and velocity profiles measurements, it indicates that the synthetic jet(SJ) could enlarge the mixing of the shear layer and then enhance the stability of boundary layer, resulting in scope reduction of the flow separation zone. Furthermore, the control effects of dual jet arrays positioned at 15%c(Actuator 1) and 40%c(Actuator 2) respectively are systematically investigated with different jet parameters, such as two typical relative phase angles and various incline angles of the jet. The jet closer to the leading edge of airfoil is more advantageous in delaying the stall of airfoil, and overall,the flow control performances of jet arrays are better than those of single actuator. At the angle of attack(Ao A) just approaching and larger than the stall Ao A, jet array with 180° phase difference could increase the lift coefficient more significantly and prevent flow separation. When momentum coefficient of the jet arrays is small, a larger jet angle of Actuator 2 is more effective in improving the maximum lift coefficient of airfoil. With a larger momentum coefficient of jet array, a smaller jet angle of Actuator 2 is more effective.     

几种金属材料在2.6～7km/s弹丸撞击下的损伤行为

研究了ＬＹ１２、ＬＦ６、ＴＡ６、３０ＣｒＭｎＳｉＡ四种靶材在２．６￣７ｋｍ／ｓＧＣｒ１５高速弹丸碰撞下的损伤行为。结果表明，弹坑深度和直径一般随弹丸速度ｖ０的增大而增大，但在４ｋｍ／ｓ〈ｖ０〈５ｋｍ／ｓ碰撞速度范围内，弹坑深度和直径随ｖ０的增大而减小。对于所研究的弹靶材料的组合，在ｖ０≈５ｋｍ／ｓ时，弹丸侵长驱支材的能力都下降到最小。在量纲理论分析基础上，应用最小二乘法处理试验数据得到２．６ｋｍ／     

单层及双层板的超高速碰撞试验(速度超过10km/s)的数值模拟

文章介绍了在Sandia国家实验室所进行的3个精确控制的超高速碰撞试验,使用两种复杂的流体码即多维流体动力学代码CTH和平滑粒子流体动力学代码SPH,对该试验进行数值模拟。该试验用质量为克大小的飞片及球形射弹以大约10km/s的速度撞击薄铝板及钢板(厚度小于1cm)。并分析了碎片云动力学计算预示结果及这些试验中金属板的损坏。