钝前缘梯形翼高超声速风洞颤振试验

Hypersonic Wind Tunnel Flutter Test for a Blunt-Leading-Edge Delta Wing

为了研究钝前缘翼面的高超声速颤振特性,获得典型翼面高超声速颤振参数以校验非定常气动力和CFD计算,采用具有简单结构动力学特性的钝前缘梯形翼模型,在中国航天空气动力技术研究院FD-07高超声速风洞进行了高超声速风洞颤振试验研究.模型为9 mm厚钝前缘梯形平板翼,采用夹层设计:中间层为钢板,提供模型主要刚度和质量特性;两侧为泡沫,起维形作用.试验模型采用悬臂支撑安装于风洞试验段,试验Mach数分别为4.95和5.95.试验固定Mach数,通过缓慢增加动压以使模型达到颤振临界点,采用小波时频谱分析时域响应,结果显示试验模型发生了弯扭耦合经典颤振.试验采用直接观测法获得了颤振动压、颤振频率和对应的试验密度、总温等颤振相关参数.采用壳单元建立了结构有限元模型,并采用统一升力面理论对模型进行了颤振计算分析,研究了气流密度、结构阻尼、Mach数对颤振计算的影响,并对试验结果与理论计算的偏差进行了讨论.分析认为,计算气流密度、计算结构阻尼、结构建模偏差、试验结果散布特性等因素均会构成计算值和试验值之间的偏差,但即便在计算中考虑上述因素,计算结果与试验值仍存在较大偏差.

In order to study the hypersonic flutter behavior of blunt-leading-edge wing and obtain the flutter critical parameters for the unsteady aerodynamic and CFD calculations,a hypersonic flutter test research was carried out in CAAA FD-07 hypersonic wind tunnel. Two blunt-leading-edge delta wings with the same structural dynamic characteristic and the same configuration were tested at Mach number 4.95 and 5.95,respectively. The model was cantilever mounted to the test rig in the test chamber. The flutter onset condition was obtained by slowly increasing the dynamic pressure until flutter actually occurred. Wavelet time-frequency analysis for the model response shows that the bending mode and torsion mode coupled during the test,which indicating a classic flutter. The flutter dynamic pressure,flutter frequency,density and total temperature were obtained in the tests. Shell elements were used in the FE（ finite element） modeling. Flutter analysis using unified lifting-surface method was made to evaluate the influence of fluid density,structural damping and Mach number effect on the flutter critical parameters. The deviation between the experimental results and theoretical calculation was also discussed. According to the analysis,factors such as air density,structural damping,the deviation of structural modeling and dispersion of test results will all make contribution to the deviations between the calculated value and experimental value. However,even if the above factors are taken into account in the calculation,there is still a large deviation between the calculation result and the test result.