NONLINEAR MATHEMATICAL MODELING OF TRANSONIC FLUTTER BY NONLINEAR DYNAMICS APPROACH

1.基于Navier-Stokes程序的机翼模型颤振分析对2001年进行的初步分析结果进行了回顾和检验。分析结果表明，尽管极限环振荡（LCO）现象可以用跨音速颤振特性来表示，但由于操纵面装有驱动电机的扩大部分引起的压力突变会造成分析困难，因此分析结果存在一些问题。后续分析将在以后的程序中处理。基于数值分析的跨音速颤振非线性数学模型的改进本文在两种模态中引入了非线性项，对非线性动力学方法导出的非线性数学模型进行了物理检验。相应地，分叉特性得到了改善，与风洞试验结果吻合较好。研究结果在与丹麦的一个合作伙伴（DTU）共同举办的一次国际会议上发表。讨论并 ...更多信息 验证了以广义坐标和广义气动力的非线性关系为重点的数学建模方法的有效性.翻新风洞试验模型和跨音速风洞试验结果支撑操纵面和连接肋的外板部分的裂缝已修复。作为福井大学和日本宇宙航空研究开发机构的合作，在该机构的跨音速风洞中使用机翼模型进行了颤振实验。在试验中，用机翼前缘操纵面作为激励器，对有操纵和无操纵状态下的机翼模型进行振动，得到了分叉数据。结果表明，在控制状态试验中，稳定边界和LCO均得到了成功的确定。这是世界范围内首次在开环和闭环颤振之间的动压下发生LCO。此外，对于亚临界动压下的非受控状态，还观察到了一种新的现象，即机翼在LCO中一旦受到激振，在去除振荡源后就停止了颤振。少

1. Flutter analysis based on Navier-Stokes code for a wing modelPreliminary analysis results conducted in 2001 has been reviewed and examined. The analytical results show that even though limit cycle oscillation (LCO) phenomena can be expressed specifying transonic flutter features, the results have some problems because an abrupt pressure change due to the enlarged part accommodating driving motors for control surfaces causes analytical difficulties. The follow-on analysis will be treated in the future program.2. Improvement of a nonlinear mathematical model for transonic flutter based on numerical analysisNonlinear terms are introduced in two modes making physical examination to nonlinear mathematical model derived in nonlinear dynamics approach. The bifurcation characteristics have been greatly improved accordingly to fit the wind tunnel test results. The results were presented at an international conference co-authored with a collaborative partner in Denmark (DTU). We discussed and … More confirmed the validity of mathematical modeling approach focusing the nonlinear relationship of generalized coordinates and the generalized aerodynamics.3. Refurbishing a wind tunnel test model and the results of transonic wind tunnel testsCracks at the part of the outer panel supporting a control surface and connecting ribs have been repaired. As the cooperation between the University of Fukui and the Japan Aerospace Exploration Agency, flutter experiment using a wing model at the agency's transonic wind tunnel has been carried out. In the tests bifurcation data have been obtained vibrating the wing model using its leading edge control surface as an exciter for the states with and without control. As a result, stability boundary and LCO have been successively confirmed in the test for controlled state. It is worldwide first time that LCO can happen at the dynamic pressure between the open loop and the closed loop flutter. Furthermore, for uncontrolled state at the subcritical dynamic pressure, a new phenomenon has been observed that the wing excited once staying in LCO then ceased flutter after removing the oscillation source. Less