民用运输类飞机最小操纵速度试飞对比研究

根据运输类飞机适航标准中CCAR25.149条最小操纵速度的型号合格审定试飞要求,对民用运输类飞机在适航取证过程中需要通过试飞验证的三种最小操纵速度考察的飞行阶段、试飞限制条件及要求、试飞方法等进行了对比分析研究,最后结合分析结果给出试飞计划安排。可供民用运输类飞机最小操纵速度适航试飞参考。     

翼梢小翼形态对某民机低速气动特性的影响

本文针对某民用飞机着陆构型,通过计算流体力学(Computational Fluid Dynamics,CFD)方法研究了不同翼梢小翼形态对该着陆构型气动特性的影响。研究结果表明:不同小翼形态翼尖流动状态不同,对分离的控制不同,且能改变飞机的纵向力矩特性。     

有趣的数卡游戏

正今天,妈妈和我一起做数卡游戏,就是从0、1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、22这些数卡中,用三个数卡组成一个加减混合算式,得数是24,每个数卡都必须用到,而且只能用一次,看谁用的时间最少。我飞快地看了一眼,在纸上写起数学算式来:14-12+22=24;1+4+19=24;2+5+17=24;16-10+18=24;11+6+7=24;3+13+8=24;15+9+0=24。     

一种基于神经网络的任意模型参考自适应控制

针对一般模型参考自适应控制方法在解高阶非线性模型时参考模型阶数较高的不足,采用一种任意模型参考自适应控制降低了参考模型的难度。利用隐层神经网络对模型进行逼近,对线性化时由不确定因素导致的误差进行补偿,并利用直接Lyapunov稳定性理论证明了跟踪误差有界,最后将其应用到飞行器纵向非线性模型的自动着陆下滑控制设计中。仿真结果表明,所设计的控制器能够使飞行器较好地跟踪理想着陆轨迹,从而验证了方法的有效性。     

Quantitative analysis of torrential rainfall associated with typhoon landfall： A case study of typhoon Haitang （2005）

A quantitative analysis of torrential rainfall associated with typhoon Haitang (2005) is carried out using a modified moist ageostrophic Q vector and data from Weather Research and Forecasting (WRF) model simulation. Four major factors determining the ascending motion associated with torrential rainfall have been studied: large-scale and convective condensational heating, topographic lifting and friction. The results show that the convective condensational heating plays a major role in the torrential rainfall process and the large-scale condensational heating is secondary before the landfall of typhoon Haitang, and vice versa after the landfall. The topographic lifting affects the formation of rainfall whereas the topographic friction has important impacts on torrential rainfall after the landfall. The rainfall amounts forced by topographic friction and lifting have similar horizontal distributions but the magnitudes of the former are 2－3 times larger than those of the latter. The rainfall amounts forced by topography (lifting and friction) and modified moist ageostrophic Q vector have different horizontal distributions and the magnitudes of the former are 2－5 times larger than those of the latter. Synthetic analysis shows that the typhoon rainfall may be motivated by modified moist ageostrophic Q vector and enhanced further by the topographic effects.     

微波着陆系统模型试验环境模型的实现

飞行检验仿真对实际飞行检验意义重大。根据微波着陆系统的技术体制和导航原理,设计并建立了机场微波着陆系统基于缩比模型的激光模拟飞行检验半实物仿真系统。主要研究了微波着陆系统半实物仿真系统的环境模型的实现理论和技术,以及机场典型环境模型材料的制备技术。以某机场为原型,建立其模型试验系统,并给出了试验结果。试验结果表明：微波着陆系统模型试验系统可以模拟实际机场场地环境的对微波着陆系统的影响。