摘要：机机翼前缘结冰会改变机翼的气动轮廓并影响整体的空气动力学性能.研究简化角冰冰形对翼型绕流流场结构的影响可以为飞机防冰设计提供有价值的参考.采用粒子图像测速技术,在低速直流风洞中对覆盖不同角冰冰形的翼型在不同攻角时的流场结构进行了详细的实验测量.实验对象包括三种简化的冰形和原始冰形.结果表明,在本研究范围内,覆盖简化冰形的翼型和覆盖原始冰形的翼型在流场参数上的最大差异为35.11%.与原始冰形相比,覆盖简化的角冰冰形的翼型流场中的分离泡距离翼型前缘和后缘更远.在三种冰形简化方法中,将冰角简化成矩形并在冰角之间添加抛物线的连接方式具有比较好的简化效果.在选定的两个区域中,这种简化冰形和原始冰形在翼型绕流流场的参数平均值的差异在14.88%之内.

摘要：In this paper,a coupled CFD-CSD method based on N-S equations is described for static aeroelastic correction and jig-shape design of large *** wing structural flexibility matrix is analyzed by a finite element method with a double-beam *** viscous multi-block structured grid is used in aerodynamic *** matrix interpolation is fulfilled by use of a surface spline *** load distributions on wing surface are evaluated by solving N-S equations with a parallel algorithm.A flexibility approach is employed to calculate the structural *** successive iterations between steady aerodynamic forces and structural deformations,a coupled CFD-CSD method is achieved for the static aeroelastic correction and jig-shape design of a large *** present method is applied to the static aeroelastic analysis and jig-shape design for a typical large airliner with engine nacelle and *** numerical results indicate that calculations of static aeroelastic correction should employ tightly coupled CFD-CSD iterations,and that on a given cruise shape only one round of iterative design is needed to obtain the jig-shape meeting design requirements.

摘要：介绍了应用液压驱动形式构建风洞动态试验控制系统的软硬件设计方法,包括液压马达、伺服阀的参数计算及选型,液压伺服位置控制系统设计方案,基于前馈控制和模糊比例-积分-微分(Proportion-Integration-Differentiation,PID)控制算法的设计思路,简谐运动的实现方法等。通过试验数据分析,该套系统在5°/2.5 Hz和40°/0.8 Hz以下的振幅/频率组合指标运动下,满足幅值差10%和相位差10°以内的控制指标要求,同时分析得到伺服阀死区特性是运动频率对指标造成影响的主要原因,并得出了基于液压驱动的动态试验系统较传统电机驱动系统的优缺点。

摘要：Intensive use of geometrical modelling started with the development of computer graphics and CAD/CAM technologies, comprising a wide area of mathematical disciplines. Geometrical modelling is a synthesis of the geometry and computer graphics, which enable us to develop complex mathematical models that would be rather difficult to display without using a computer. The author recognizes two basic methods of research of geometrical models, synthetic and analytic. The synthetic method makes use of geometrical constructions and in the analytic method geometrical objects are characterized by numerical data. The author uses these methods in this contribution. The aim of this research is to show central cyclides (Dupin s cyclides) as a special kind of the cyclical elliptical pedal surfaces. Firstly, applying the method of synthetic geometry, a new class of such surfaces in the 3-dimensional Euclidean space (model of the projective space) is defined. The geometrical construction of these surfaces is dependent on the given ellipse and the position of the pole P. It is the point at which the pencil of perpendicular planes passes to the plane of the ellipse, wherein the generating circles of the surface are lying. The parametric equations of the cyclical elliptical surface are derived applying the method of analytic geometry. The author classifies the surfaces according to the number of generating circles with a zero radius. The evolute of the ellipse divides the plane of the ellipse into two areas,Ω1 and Ω2. The shape of the surface depends on the position of the pole P in the areas of Ω1 and Ω2. The surface can have 4, 3 or 2 circles with a zero radius. The author then describes the relationship between these surfaces and the Dupin s cyclides, obtained in the case when the pole P is the point on the major axis of the ellipse. Finally, the transformation of these surfaces is shown by changing of the orthonormal base in the parameterization of the generating circles of the surf