大跨度桥梁抖振响应研究

简要介绍了处于自然大气湍流中的大跨度桥梁易发生的风振形式之一的抖振概念以及分析抖振的频域法和时域法 ,概括地介绍了中国空气动力研究与发展中心低速所在该方向上的一些研究工作以及拟开展的研究工作。     

从摄动理论看洞壁干扰的总体型修正

利用Ｄ．Ｎｉｘｏｎ跨声速摄动理论对目前奉行的洞壁干扰总体型修正提出了质疑;讨论了结果从理论上进一步支持了洞壁干扰的当地型修正战略。     

模型旋翼风洞试验中变距拉杆载荷的测量

桨叶变距拉杆操纵载荷是旋翼设计的重要参数之一。在参考了常规飞机模型风洞试验测力元件及国外测量方法的基础上,研制了具有足够刚度和强度,且有较高载荷灵敏度的新式变距拉杆测力元件,解决了高刚度与高的载荷灵敏度要求这一矛盾。同时采用了信号放大技术,将其成功地应用于旋翼模型试验,并获得了操纵载荷这一重要参数     

低速闭口风洞模型张线支撑及内天平测量系统的研制

“张线支撑及内天平测量系统”已在ＦＬ－８ 闭口风洞中调试、使用。该系统使用了套管天平,套管内杆是天平与模型相连,与天平相连的套管是支撑体,张线的一端与套管的前后吊点相连,张线的另一端与风洞上转盘齿圈上的张紧机构和风洞下转盘下的配重相连。该系统的角度变化范围,模型侧吊时, α＝ ±３６０°,β＝ ±６５°,模型正吊时,α＝ ±６５°,β＝ ±３６０°实验表明：张线支撑与尾撑和腹撑相比,消除了由于支杆引起的模型振动,其支架干扰变小,试验数据质量有了进一步的提高     

弹性模型实验技术

介绍了火箭弹性模型实验技术,包括模型对火箭的质量分布、刚度分布的模拟,模型的加工制做,激振机构的研制,支撑元件的研制以及几期实验的结果综合。     

Influence of shock attenuation on tailored operation in free piston shock tunnels

The free piston shock tunnel is a type of shock tunnel with high performance. For this type of tunnel, the influence mechanism of shock wave attenuation on tailored operation is explored by numerical simulation and theoretical analysis. By introducing the normalized velocity, the simple constraint equation for shock wave under the tailored operation is deduced. Moreover, the real gas effect is also taken into account in this equation. Based on the equation, the tailored operation of shock tunnels can be predicted with very few calculations. The present study shows that the change rate of the thermodynamic state of the gas behind the shock wave is inconsistent with the attenuation rate of the shock wave, which is the fundamental reason why the wind tunnel achieves tailored operation at a lower Mach number of shock waves. This lower Mach number of shock waves differs from the corresponding ideal value by a factor, which is about the square root of shock attenuation rate.     

A hybrid original approach for prediction of the aerodynamic coe?cients of an ATR-42 scaled wing model

A new approach for the prediction of lift, drag, and moment coefficients is presented. This approach is based on the support vector machines (SVMs) methodology and an optimization meta-heuristic algorithm called extended great deluge (EGD). The novelty of this approach is the hybridization between the SVM and the EGD algorithm. The EGD is used to optimize the SVM parameters. The training and validation of this new identification approach is realized using the aerodynamic coefficients of an ATR-42 wing model. The aerodynamic coefficients data are obtained with the XFoil software and experimental tests using the Price–Pa?doussis wind tunnel. The predicted results with our approach are compared with those from the XFoil software and experimental results for different flight cases of angles of attack and Mach numbers. The main pur-pose of this methodology is to rapidly predict aircraft aerodynamic coefficients.     

TUNNEL INTERFERENCE IN UNSTEADY POST-STALL EXPERIMENTS

ＴＵＮＮＥＬＩＮＴＥＲＦＥＲＥＮＣＥＩＮＵＮＳＴＥＡＤＹＰＯＳＴ┐ＳＴＡＬＬＥＸＰＥＲＩＭＥＮＴＳＺｈａｎｇＷｅｎｈｕａ，ＤｉｎｇＫｅｗｅｎ，ＨｕａｎｇＤａ，ＬｉＺｈｉｑｉａｎｇ，ＺｈａｎｇＱｉｎｇｌｉ（６ｔｈＤｅｐｔ．ＮａｎｊｉｎｇＵｎｉｖｅｒｓｉ...     

钝体涡激力参数的识别

涡激振是柔性结构易发生的气动弹性现象。本文通过风洞试验，研究了均匀流场中弹性支承的二维刚性模型的强激力，提出了一种识别涡激力模型中未知参数的方法。用本文的方法，进行了三种钝体模型的风洞试验。     

FL-1风洞绘图软件

本文介绍了用于 FL-1风洞实验的绘图软件结构、功能和操作。