飞行轨迹稳定性应用的分析

首先根据飞行轨迹稳定性的数学模型，得出了飞机在闭环条件下扰动过程速度的变化规律及飞行轨迹稳定性的应用条件，并且结合不同类型的飞机进行了对比分析。然后以推力曲线为基础分析了不同类型飞机的临速度范围，并根据飞机级曲线对飞行轨迹稳定性界状态与有利速度的关系进行了分析。     

飞机在尾旋中侧滑和坡度的分析

分析了在飞机在尾旋中产生侧滑和坡度的根本原因，论述了侧滑和坡度在尾中的变化的规律，影响侧滑和坡度的因素，以及侧滑和坡度变化对尾旋动态的影响，同时就尾旋中偏滚对尾旋侧滑的影响，绕铅垂旋轴对坡度的影响等进行了讨论分析，最后通过分析ＪＪ６飞机和ＪＪ５飞机尾旋的测试曲线，进一步说明了ωｘ和ωｙ对坡度的影响，可为飞行员掌握尾旋特性，提高飞行技术和保证飞行安全提供参考。     

A model of galactic cosmic rays for use in calculating linear energy transfer spectra.

The galactic cosmic rays (GCR) contain fully stripped nuclei, from Hydrogen to beyond the Iron group, accelerated to high energies and are a major component of the background radiation encountered by satellites and interplanetary spacecraft. This paper presents a GCR model which is based upon our current understanding of the astrophysics of GCR transport through interstellar and interplanetary space. The model can be used to predict the energy spectra for all stable and long-lived radioactive species from H to Ni over an energy range from 50 to 50,000 MeV/nucleon as a function of a single parameter, the solar modulation level phi. The details of this model are summarized, phi is derived for the period 1974 to present, and results from this model during the 1990/1991 CRRES mission are presented.     

航天运载器的电气系统数字化研制技术

针对运载器电气系统的数字化,给出研制过程中层次的划分、研制的关键环节及相互关系,并对运载器电气系统的数字样机技术和产品全生命周期管理技术进行扼要的分析,最后给出完整的应用系统框架结构。为运载器的数字化研制作了重要的补充。     

侧滑对后掠翼飞机俯仰操纵影响的探讨

运用基础理论，对后掠翼飞机出现侧滑时的地仰状态变化进行分析。文中推导了后掠翼飞机的后掠角在有侧滑时对升力的影响，以及下洗角大小和分布的变化在水平尾翼处引起的俯仰力矩变化。通过时几种飞机的计算和分析比较，说明了后掠角在侧滑中具有提供上仰力矩的作用，从而在理论上解决了大后掠角飞机（如Ｊ—６飞机）出现侧滑时的急剧上仰现象和操纵措施问题，为在飞行中出现偏差进行修正提供了理论依据。对提高飞行员的驾驶技术和保证飞行安全有着积极的作用。     

GPS伪卫星组合定位方法及在变形监测中的应用

针对GPS在城市高楼密集区、深山峡谷等区域所跟踪的可见星数目少且分布不佳导致定位精度下降,以及GPS系统本身在垂直方向定位精度较差的问题,提出GPS伪卫星组合定位新方法,利用伪卫星增强GPS技术提高定位精度。建立了GPS和伪卫星组合定位的观测模型,分析了伪卫星多路径效应的特点,给出了减弱伪卫星多路径误差的有效方法。对某大坝坝区的实测数据进行处理的结果表明,文中所提出的方法能有效地减弱伪卫星多路径效应产生的误差,GPS和伪卫星组合定位方法提高了系统的定位精度,特别是垂直方向的精度。     

人员离机轨迹数值模拟及快速预测研究

离机轨迹研究在分析外挂物分离、导弹投放以及人员空中脱离过程等方面有着重要的参考意义。运用动态嵌套网格技术,通过CFD方法来模拟人员空中离机后的运动轨迹。提出一套基于本征正交分解(POD)方法的人员离机轨迹快速预测算法。将CFD数值模拟得出的离机轨迹作为样本,以飞行马赫数和攻角双参数变化为例,详细介绍POD方法预测离机轨迹的实现步骤。结果表明:POD方法相对于CFD方法可以大大减少计算时间,并且POD预测结果与CFD方法得到的结果吻合较好,为离机轨迹预测在工程应用上提供了一种快速简便的方法。     

飞机进气道／发动机匹配工作流场测试和分析

在介绍全尺寸飞机进气道／发动机匹配工作流场测试系统的基础上,给出了在发动机前安装飞机前机身后,在南面台架试车时测得的进口压力场数据,计算了进口压力场的畸变指数,分析了流场畸变图谱。     

Separation control on NACA23012 using synthetic jet

A numerical study of separation control has been made to investigate aerodynamic characteristics of NACA23012 airfoil with synthetic jets. Computed results demonstrated that stall characteristics and control surface performance could be substantially improved by resizing separation vortices. The maximum lift was obtained when the separation point coincides with the synthetic jet location and the non-dimensional frequency is about 1. In addition, separation control effect was proportional to the peak velocity of the synthetic jet. It was observed that the actual flow control mechanism and flow structure is fundamentally different depending on the range of synthetic jet frequency. For low frequency range, small vortices due to synthetic jet penetrated to the large leading edge separation vortex, and as a result, the size of the leading edge vortex was remarkably reduced. For high frequency range, however, small vortex did not grow up enough to penetrate into the leading edge separation vortex. Instead, synthetic jet firmly attached the local flow and influenced the circulation of the virtual airfoil shape which is the combined shape of the main airfoil with the separation vortex. As a way to reduce the jet peak velocity, performance of a multi-array synthetic jet was investigated. Moreover, a high frequency multi-location synthetic jet was exploited to efficiently eliminate the unstable flow structure which was observed in low frequency range. Finally, by changing the phase angle in multi-location synthetic jets, highly controlled flow characteristics could be obtained with multi-array/multi-location synthetic jets. This shows efficiency of the current approach in separation control using synthetic jet.     

Enhancing the efectiveness of film cooling

Advanced gas turbine stages are designed to operate at increasingly higher inlet temperatures to increase thermal efficiency and specific power output.To maintain durability and reasonable life,film cooling is needed in addition to internal cooling,especially for the first stage.Film cooling lowers material temperature by forced convection inside film-cooling holes and by forming a layer of coolant about component surfaces to insulate them from the hot gases.Unfortunately,each cooling jet forms a pair of counter-rotating vortices that entrains hot gas and causes the film-cooling jet to lift off from the surface that it is intended to protect.This paper gives an overview of efforts to enhance the effectiveness of film-cooling.This paper also describes two new design concepts.One design concept seeks to minimize the entrainment of hot gases underneath of film-cooling jets by using flow-aligned blockers.The other design concept shifts the interaction between the approaching hot gas and the cooling jet to occur further above the surface by using an upstream ramp.For both design concepts,computational fluid dynamics results are presented to examine their usefulness in enhancing film-cooling effectiveness.