基于80C31的手动测量装置CPM3板的 电路原理及故障处理

CPM3板是手动型测量机电控系统的核心部分，它具有一定的运动控制、采点计数以及自检功能。本文主要从调试和维修的角度探讨了CPM3板的电路设计原理，以及相应维修方法。     

跨声速三角翼旋涡破裂过程的数值模拟

本文利用张涵信提出的时，空二阶精度的隐式混合通量分裂的ＮＮＤ格式，通过求解非定常ＮＳ方程模拟了马赫数Ｍ为０．８、迎角α为２１．８°时某外形三角翼背风区旋涡破裂的发展，演变过程，并对旋涡区域的截面流态和涡轴上奇点附近的空间流动特征进行了分析。     

Numerical investigation of unsteady vortex breakdown past 80°/65° double-delta wing

An improved delayed detached eddy simulation （IDDES） method based on the k-x-SST （shear stress transport） turbulence model was applied to predict the unsteady vortex breakdown past an 80o/65o double-delta wing （DDW）, where the angles of attack （AOAs） range from 30° to 40°. Firstly, the IDDES model and the relative numerical methods were validated by simulating the massively separated flow around an NACA0021 straight wing at the AOA of 60°. The fluctuation properties of the lift and pressure coefficients were analyzed and compared with the available measurements. For the DDW case, the computations were compared with such mea-surements as the mean lift, drag, pitching moment, pressure coefficients and breakdown locations. Furthermore, the unsteady properties were investigated in detail, such as the frequencies of force and moments, pressure fluctuation on the upper surface, typical vortex breakdown patterns at three moments, and the distributions of kinetic turbulence energy at a stream wise section. Two dominated modes are observed, in which their Strouhal numbers are 1.0 at the AOAs of 30°, 32° and 34° and 0.7 at the AOAs of 36o, 38° and 40°. The breakdown vortex always moves upstream and downstream and its types change alternatively. Furthermore, the vortex can be identified as breakdown or not through the mean pressure, root mean square of pressure, or even through correlation analysis.     

MA700飞机工作分解结构方法研究

介绍了项目工作分解的概念,以及航空领域的应用情况。针对MA700飞机可能遇到的问题,提出相应的解决思路。     

尖顶襟翼长度对三角翼前缘涡破裂的影响

为了抑制三角翼前缘涡破裂的发生,研究了大攻角下(30°～50°)尖顶襟翼对70°三角翼前缘涡破裂的影响.在静态实验情况下,尖顶弯折对三角翼前缘涡破裂影响的参数有2个:尖顶襟翼弯折的角度及其长度.染色液流态显示结果表明:尖顶襟翼的向下弯折减小了靠近襟翼翼面的有效攻角,从而推迟了前缘涡破裂的发生,涡破裂位置随弯折角的变化呈非线性变化且弯折襟翼越长效果越好,α=35°时两个弯折组合的效果要比单个弯折的好.     

Transonic wing stall of a blended flying wing common research model based on DDES method

Numerical simulation of wing stall of a blended flying wing configuration at transonic speed was conducted using both delayed detached eddy simulation(DDES) and unsteady Reynolds-averaged Navier-Stokes(URANS) equations methods based on the shear stress transport(SST) turbulence model for a free-stream Mach number 0.9 and a Reynolds number 9.6 × 10~6. A joint time step/grid density study is performed based on power spectrum density(PSD) analysis of the frequency content of forces or moments, and medium mesh and the normalized time scale0.010 were suggested for this simulation. The simulation results show that the DDES methods perform more precisely than the URANS method and the aerodynamic coefficient results from DDES method compare very well with the experiment data. The angle of attack of nonlinear vortex lift and abrupt wing stall of DDES results compare well with the experimental data. The flow structure of the DDES computation shows that the wing stall is caused mainly by the leeward vortex breakdown which occurred at x/x_(cr)= 0.6 at angle of attack of 14°. The DDES methods show advantage in the simulation problem with separation flow. The computed result shows that a shock/vortex interaction is responsible for the wing stall caused by the vortex breakdown. The balance of the vortex strength and axial flow, and the shock strength, is examined to provide an explanation of the sensitivity of the breakdown location. Wing body thickness has a great influence on shock and shock/vortex interactions, which can make a significant difference to the vortex breakdown behavior and stall characteristic of the blended flying wing configuration.     

破裂涡流中非定常现象与频率特性实验研究

通过流动显示、表面动态压力测量及热线测量等实验手段,对三角翼破裂涡流中的多种频率成分进行了分析。频谱分析确定了破裂点脉动和螺旋波的频率特征。实验结果表明,螺旋波主频随着弦向位置的增大先是迅速而后平缓减小。前缘涡破裂点振动具有准周期性,在不同的弦向位置上主频大小几乎没有改变,在靠近破裂点的位置有较大的振动能量。实验分析还表明,在破裂涡的流动状态下,虽然没有形成完全分离流,三角翼绕流流场中已经存在涡脱落的现象。     

高马赫数来流条件下斜激波与流向涡对相互作用

针对斜激波入射流向涡对形成的复杂流动干扰现象,在来流马赫数6条件下,利用后掠斜坡式涡流发生器生成流向涡对,采用数值模拟结合激波风洞实验,研究了斜激波与流向涡对相互作用引起的激波变形和旋涡演变。结果表明,斜激波与流向涡对相互作用的剧烈程度大致分为强、中、弱三种。在强相互作用下,激波面向上游凸起的程度最剧烈,呈现类“T”字型特征,其对称面处接近于一道正激波,波后出现回流区和局部流动滞止,使得流向涡对发生破碎;在中等相互作用下,对称面处存在局部正激波,但没有出现回流区;在弱相互作用下,不再出现局部正激波。进一步地分析发现,斜激波与流向涡对相互作用产生的流向涡对破碎现象,不符合经典的激波作用下单个流向涡破碎理论的预测。采用流向涡对对称面处的气流参数,对经典的流向涡破碎理论进行修正后,能够预测本文流向涡对在斜激波作用下是否发生破碎。本文为掌握激波作用下流向涡对破碎现象的规律,提供了重要参考。     

雷电地面电场分布的3维 DBM模型仿真参数影响分析

采用荷电圆盘雷云解析模型作激励源,利用电介质击穿模型进行了地闪先导放电高分辨力3维数值模拟,得到了先导近地500 m时概率指数和击穿发展阈值对地面电场分布的影响。通过计算机模拟,得到了概率指数η和击穿阈值Ecrit对地面电场分布的影响,同时也验证了这2个参数对建立放电模型的重要性,为通过这一模型进行任意雷电发生时的地面电场分布模拟奠定了基础。