翼身连接处几何参数优化匹配的流动机理仿真

飞机由各个部件组装成为一个整体,在各个连接部位彼此气流互相干扰,会导致干扰阻力增加,严重影响飞机大迎角下的气动性能,因此,优化连接部位几何参数匹配对减小干扰阻力及改善飞机大迎角流动具有重要的工程应用价值.以某一特定飞机的机翼-机身的连接部位着陆构型为研究对象,采用数值模拟的方法,从连接部位的前缘、展向中段及后段3个方面...     

Fuzzy Clustering in Problems of Determining the Aerodynamic Characteristics and Modeling the Aircraft Dynamics

A modified method of fuzzy clustering is proposed for determining the aerodynamic characteristics of an aircraft from flight test data. This approach allows one to describe the aerodynamic characteristics of an aircraft in the form of a black box model with inputs in the form of telemetry data, such as accelerations, angular velocities, thrust, and dynamic pressure, and with outputs in the form of dimensionless aerodynamic coefficients of forces and moments. Results of modeling in the MATLAB/Simulink environment are reported.     

Modeling and experiment of a morphing wing integrated with a trailing edge control actuation system

Morphing wing has attracted many research attention and effort in aircraft technology development because of its advantage in lift to draft ratio and flight performance.Morphing wing technology combine...     

Control reversal and torsional divergence analysis for a high-aspect-ratio wing

Modern aircraft tends to adopt more flexible wing structures, such as high-aspect-ratio wings. They also feature advancements in performance, such as increased flight speeds. Thus, their aeroelastic characteristics and related safety factors became more important. By analyzing the static aeroelasticity of aircraft accurately, such as the control reversal and torsional divergence speed, it is expected that safe flights can be guaranteed within a prescribed flight envelope. In this paper, the control surface effectiveness and torsional divergence were analyzed using the following engineering tools: nonlinear multi-body dynamic analysis, DYMORE, cross-sectional analysis, two-cell analysis or VABS, and two-dimensional aerodynamic coefficient analysis for the subsonic isolated airfoil XFOIL. The results were verified through comparisons with those based on a typical section model with thin strip theory. Aluminum and composite single-cell box beam wings were analyzed in this paper. It is found that the control reversal and torsional divergence flight speeds as measured here were in good agreement with those predicted by a typical section model.     

某型无人倾转旋翼机过渡轨迹设计技术研究

过渡模式是倾转旋翼机全过程自主飞行的关键阶段,亦是最容易发生安全事故的阶段.过渡轨迹是飞行器过渡模式控制律和制导律设计的基础,以某型无人倾转旋翼机为研究对象,分析其气动特性,并根据过渡阶段的升力来源,将整个过渡阶段进行细化;再根据各个阶段的约束条件确定其倾转过渡走廊;依据飞行器的飞行过程以及走廊确定飞行器的过渡轨迹,并...     

小型通用飞机翼根气动性能及流动机理研究

小型通用飞机通常需要采用相对简单的增升系统及自身良好的气动性能以满足起飞和着陆阶段的安全和效益的匹配要求,这些与大迎角空气动力学特性有关。而控制翼身结合部的流动分离, 对改善小型飞机的大迎角性能具有重要的工程应用价值。通过数值模拟的方法,对某一典型通用飞机外形的着陆构型的气动性能及翼根处的流动机理研究得出,翼根处产生的马蹄涡及边角涡以及根部前缘吸力峰增高是导致翼根气流分离的主要原因,由此可通过前缘整流、展向整流和中后段三方面进行相关的整流方案设计。     

四参数变弯度翼型的气动特性分析与优化设计

针对NACA 0012翼型,在马赫数为0.176的来流条件下,首先利用数值模拟研究了翼型前缘下弯角度、前缘偏转位置、后缘下弯角度和后缘偏转位置等因素对翼型气动性能的影响规律;其次,以升阻比为目标,上述4个因素为设计变量,利用神经网络建立升阻比与4个设计变量间的预测模型;然后,充分考虑优化精度和神经网络训练数据库的计算量,构造了一种翼型优化过程与神经网络预测耦合的迭代优化策略,基于该优化策略得到最优变弯度翼型构型。对比优化翼型和原始翼型,升阻比提高约22%,较大程度改善了翼型的气动特性;并且通过远场噪声分析,发现优化翼型表现出了较好的声学性能,在1 000 Hz附近单音噪声最大可降低12 dB。     

变体飞行器及其变形驱动技术

变体飞行器可以根据飞行环境的不同,自主地改变气动外形,更有效地完成飞行任务,是目前国内外飞行器领域的研究热点之一。回顾了早期刚性变体飞行器、柔性变体飞行器及其变形驱动技术的发展过程。通过对应用于变体飞行器的各种智能材料及作动器的性能特点的比较,总结出一种新型的压电作动器——超声电机在变体飞行器变形驱动上的技术优势,提出了利用超声电机来驱动小型变体飞行器变形所要研究的关键问题。     

组合动力验证机助推段纵向控制器设计

针对飞行器的飞行特点和自身的气动结构,建立复杂的非线性数学模型,给出静稳定性和模态特性的分析.为解决高超声速飞行器在助推段因纵向静不稳度大而导致的常规控制律鲁棒性不足的问题,设计基于角速率指令内回路的纵向控制律,并从时域、频域、鲁棒性三方面进行分析,得出指令内回路适用于助推段纵向控制的结论.     

机翼模型应变场分布式光纤监测与重构方法

针对飞行器机翼结构应变场重构问题,提出了一种基于分布式光纤传感器与模态叠加原理相结合的大展弦比机翼缩比模型应变场监测与重构方法。借助ANSYS有限元分析软件,数值模拟得到大展弦比机翼缩比模型在不同载荷下应变分布与应变模态振型。在此基础上,通过在大展弦比铝合金机翼缩比模型展向设置光纤Bragg光栅传感器,实时采集应变分布与变化信息,结合数值仿真得到机翼模型应变模态振型,重构机翼缩比模型应变场分布,应变反演平均误差约为7%。研究结果表明,本研究方法具有非视觉测量、实时性好以及反演精度较高等优点,能够为及时准确获取飞行器翼面应变场分布信息,进而实现机翼气动载荷计算与疲劳寿命预测提供技术支撑。