【作者】 吴志强； 张建伟；

【Author】 WU Zhiqiang,ZHANG Jianwei(Departmant of Mechanics,Tianjin University,Tianjin,300072,China)

【机构】 天津大学力学系；

【摘要】 机翼颤振是飞机飞行中最常见的、可能带来灾难性后果的气动弹性现象,属于自激振动。揭示其机理和规律,对机翼和飞行器设计有重要意义。以二元机翼模型为例,通过数值计算Poincare映射分岔的方法,讨论了极限环颤振随气流速度变化引起的复杂分岔行为。对自治非线性系统,还没有公认的方法选取合适的Poincare截面,特选俯仰角加速度为零的点作为广义Poincare截面上的点。通过考察广义Poincare截面上点的数目随参数的变化来考察系统的分岔。计算出了参数气流激振力变化导致的分岔图,并给出了8种不同的具有代表性的典型的相图和谱图,对应8种闭轨曲线的拓扑形状各不相同,发现系统中存在正向和反向的超谐分岔是产生这种闭轨分岔的根源。更多还原

【Abstract】 The airfoil flutter is a self-excited aeroelastic phenomenon which may lead to catastrophe in aircraft flight.Its mechanism and rules are very important for wing and aircraft design.For a two degree-of-freedoms airfoil model,the bifurcation behaviour of its limit-cycle flutter induced by the variation of the air flow velocity is investigated numerically by the Poincare map method.The Poincare section is defined in the way so that it insects the orbit when the pitch angular acceleration crosses zero increasingly.The bifurcation diagrams due to the variation of the fluid force are presented as well as the eight different typical phase portraits and the corresponding amplitude spectra.It is found that the bifurcation sequence is formed by a series of superharmonic bifurcations which result in the eight phase portraits topologically different.更多还原