捷联惯性航姿系统中的模糊内阻尼算法研究

舒勒周期振荡和傅科周期振荡会影响捷联惯性航姿系统的精度。本文将传统的平台内阻尼的思想引入到捷联惯性航姿系统中，通过设计水平回路中的三阶内阻尼网路，利用系统本身的速度信息来阻尼周期振荡。由于改变了舒拉调整条件，内阻尼算法只有在系统加速度较小的情况下才能使用。文中根据模糊理论对三轴加速度计的输出分析系统运动状态，判别是否能够使用内阻尼网路。仿真和实验证明，模糊内阻尼算法明显抑制了舒勒周期振荡和傅科周期振荡，有效提高了捷联惯性航姿系统精度。     

4m×3m风洞无人机模型振动抑制系统研制

在4m×3m低速风洞大展弦比无人机试验中,出现了纵向大振幅振动问题.通过试验观察和支撑系统的有限元计算,在不破坏风洞结构和不改变原模型姿态角变化范围的条件下,气动中心低速所研制了一套抑振装置.该装置成功应用于多个无人机型号试验,有效地抑制了纵向大振幅振动,提高了大展弦比无人机低速风洞试验数据的精准度.     

飞机偏航-滚转耦合运动非定常空气动力实验

在3m低速风洞中设计制造了一套动态实验系统，不仅能模拟飞机单自由度机动飞行运动．还能实现模型绕体轴的偏航-滚转耦合运动。通过选择运动参数．可实现绕两个轴运动角速度之间的匹配，满足飞机典型机动飞行所需的绕速度轴的无侧滑偏航一滚转运动。试验测量了BJ-1飞机模型在不同迎角下单独滚转、单独偏航和偏航-滚转耦合运动时的非定常气动特性。结果表明，飞机机动飞行时多自由度运动的气动特性比单自由度运动气动特性复杂，耦合运动时的气动特性与两个单自由度运动的气动特性的叠加结果相比有很大差别。     

机动襟翼对纵向PIO的影响

机动襟翼在我国是一项刚被采用的新技术，而驾驶员诱发振荡是严重威胁飞行安全并一直困扰航空界的一大难题，主要通过对机动襟翼调节规律的分析，建立包括机动襟翼在向的人－机闭环系统数学模型，从而计算了分析机动襟翼对纵向驾驶员诱发振荡的影响，并以某机为例，对该机机动襟翼整个工作范围内的各飞行状态，有无机动襟翼两种情况下的ＰＩＯ进行了仿真计算。结果表明，机动襟翼设计合理，对ＰＩＯ影响不大。     

利用气动弹性的柔性振翼模型建立及分析(英文)

Making use of modal characteristics of the natural vibration of flexible structure to design the oscillating wing aircraft is proposed. A series of equations concerning the oscillating wing of flexible structures are derived. The kinetic equation for aerodynamic force coupled with elastic movement is set up, and relevant formulae are derived. The unsteady aerodynamic one in that formulae is revised. The design principle, design process and range of application of such oscillating wing analytical method are elaborated. A flexible structural oscillating wing model is set up, and relevant time response analysis and frequency response analysis are conducted. The analytical results indicate that adopting the new-type driving way for the oscillating wing will not have flutter problems and will be able to produce propulsive force. Furthermore, it will consume much less power than the fixed wing for generating the same lift.     

Shortcomings of the Standard Solar Model

The SSM, invented in early nineteen sixties, remains a useful construction. There are now much larger number of its predictions that may be compared with observations than when it was first introduced. Seismic sounding based on oscillations frequencies provides the best test of the physical input for modelling stellar evolution. The results of the test must be viewed as a support for the standard theory of stellar evolution. However, significant differences in the sound-speed, photospheric He abundance, and other parameters between the Sun and the current models remain. Shortcomings in the EOS and in treatment of convection have been revealed. The differences in the sound-speed in the radiative interior may be explained by small opacity errors but other explanations are possible. Results of seismic sounding support the idea that the element mixing in the outer part of the radiative interior occurred during a significant fraction of the Sun's life. Such mixing is considered as a possible explanation of the deficit of lithium. The shortcomings of SSM cannot explain the deficits of measured neutrino fluxes. This revised version was published online in June 2006 with corrections to the Cover Date.     

刷式密封刷丝变形与振动特性实验

刷式密封刷丝运动变形引起的泄漏损失、刷丝断裂等问题较为突出。本文分析刷式密封刷丝运动变形理论模型，设计搭建刷式密封刷丝变形与振动特性观测实验装置，设计加工了3种周向倾角的低滞后型刷式密封实验件，实验观测并研究刷式密封刷丝轴向变形特性，刷丝吹下效应、刷丝分层和刷丝振动特性，揭示刷式密封刷丝运动状态。研究结果表明，在进出口压比1.5~4工况下，刷式密封刷丝自由端轴向变形量随着压比的增大而近似线性增加，周向倾角对刷丝轴向变形影响不大。刷式密封前排刷丝吹下效应明显强于后排刷丝，随着周向倾角的增大，刷式密封刷丝吹下效应逐渐减弱，在本文研究工况下，周向倾角为50°、55°和60°的刷式密封刷丝最大吹下量分别为0.60、0.45和0.34 mm。刷式密封刷丝产生分层现象的主要原因是在气流力的作用下，刷丝束轴向产生变形，刷丝束自由端在不相等的转子表面轴向摩擦力作用下，刷丝束进一步产生不同步的变形量，导致刷丝束出现间隙进而形成刷丝分层现象。刷丝振动主要发生在刷丝密度相对松散的区域，且随着压比的增大而增强，刷丝自由端位移随时间呈振荡变化，其在轴向的振幅大于周向的振幅。     

Solar Neutrinos

The current status of solar neutrino experiments is reviewed. All the experimental measurements show deficits of solar neutrinos. Non monotonic suppression indicates that the problem may naturally be explained by neutrino oscillations, but not by modifying solar models. A new experiment shows very promising results. We hope that a definite answer to the question of whether solar neutrinos are oscillating will be obtained in the very near future. This revised version was published online in June 2006 with corrections to the Cover Date.     

水下超声速气流流场非定常特性研究

上浮水雷在工作过程中环境压力大幅度变化，针对上浮水雷火箭发动机具有三种不同工作状态（欠膨胀、完全膨胀、过膨胀）的特点，采用VOF两相流模型，建立了水下火箭发动机在不同工作状态喷射流发展的轴对称计算模型，分别在来流速度0m/s和50m/s两种工况下，研究了水下发动机在不同工作状态时喷射流发展规律及流场脉动特性。结果显示，在静水条件下，欠膨胀工况时颈缩发生位置距喷管出口较远，流场压力和喉部流量没有发生脉动现象，其它工况时颈缩发生位置距喷管出口较近，完全膨胀工况和过膨胀工况喷管出口最大压力振幅分别为5.5MPa，7MPa；喷管喉部流量振动幅度约为5.2%，32.8%；在有流速条件下，三种工作状态发生颈缩、胀鼓和回击现象的位置距离喷管出口较远，完全膨胀喷管出口最大压力振幅为2MPa，喷管喉部流量未发生脉动特性，过膨胀工况喷管出口最大压力振幅6.1MPa，喉部流量振动幅度30.4%。     

环路热管温度波动现象的实验分析

对实验中观察到的环路热管温度波动现象进行了描述和解释.实验发现,较小热载荷和较大热载荷下环路热管容易出现温度波动现象.对于蒸发器充满液体的启动情况,小热载荷启动容易出现毛细芯内的工质蒸发现象,芯内蒸发继而引起冷凝器入口处的温度波动,并且最终导致可变热导区的稳态工作温度偏高.冷凝器出口处的温度波动现象产生的原因是工质充装量和储液器容积的不匹配,冷凝器出口的温度波动可以通过对工质充装量的控制来避免.