面向多学科设计的高效高保真非线性气动弹性降阶模型研究

The popular engineering aeroelastic optimization is based on the low-fidelity panel aerodynamic model, which is unsuitable for the nonlinear aeroelasticity induced by nonlinear aerodynamics. Based on the recent advances on the robust adaptive unsteady flow field reduced order model (ROM) , which is supported by the young researchers’ foundation, we further investigate the design oriented aeroelastic reduced order model and propose a new nonlinear dynamic aeroelastic tailor method for composite structural wings based on the high-fidelity aeroelastic reduced order model. The new method would provide basic algorithms for the high-fidelity CFD/CSD couple simulation based nonlinear aeroelastic tailor and integration optimization. The key issue is how to keep the accuracy and efficiency of the aeroelastic reduced order model when the design parameters are varying in the design space .The innovations include the design oriented high-fidelity high-efficiency nonlinear aeroelastic reduced order model which is insensitive to the varying of fluid and structral design parameters, and the new nonlinear aeroelastic tailor method for composite structural wing based on aeroelastic reduced order models.

目前工程上广泛应用的气动弹性设计方法，主要采用基于线性气动理论的低保真气动弹性模型，难以满足气动非线性诱导的非线性气动弹性设计精度要求。本项目在青年基金面向气动弹性仿真分析的自适应鲁棒非定常流场降阶模型（Reduced Order Model,ROM）所取得的进展基础上，进一步探索面向气动弹性设计的高效高精度ROM及其构造方法，建立基于ROM技术的复合材料机翼非线性颤振气动弹性剪裁方法,为基于CFD/CSD耦合数值模拟的气动/结构一体化设计提供方法支撑。拟解决的关键科学问题是：气动参数和结构参数在设计空间变化时，如何保持非线性气动弹性ROM的高保真度和高效率。本项目主要特色是延续性强，多学科交叉特点鲜明；主要创新点是提出面向设计的不依赖结构模态的高保真度非线性气动弹性ROM和基于ROM技术的复合材料机翼气动弹性剪裁方法。

本研究针对面向多学科设计的高效高保真非线性气动弹性降阶模型及其应用展开研究。建立了基于CFD的高精度、高效气弹系统（Reduced order model）ROM。提出了Lyapunov稳定性原理和ROM结合的非线性流固耦合系统稳定性分析方法；所建立的稳定性分析方法可以准确、高效地识别出高维非线性耦合系统的稳定性边界。建立了基于CFD的气动伺服弹性（Aeroservoelastic，ASE）ROM，提出了基于ROM的时滞颤振抑制主动控制律设计方法。将AGARD 445.6机翼气弹系统颤振边界提高了约30%。研究了时滞对跨音速气弹系统主动控制性能的影响，设计了时滞颤振抑制主动控制律。通过建立的ASE ROM设计的时滞控制律有效地抑制了时滞引起的不稳定；ASE ROM可以快速、准确地寻找到使控制系统失效的临界时滞量。提出了基于CFD的气弹系统运动阵风POD/ROM方法，相比于CFD计算效率提高了3个量级以上。建立了基于POD/ROM的危险阵风工况高效辨识方法，较CFD方法效率提高了约15000倍。设计了弹性机翼的阵风减缓主动控制律，控制系统有效地减缓了由大气湍流导致的结构振动，将结构振动响应减小了约80%。提出了基于结构重分析技术的结构参数变化时降阶模型快速重构方法，大大提高了气动弹性系统结构参数变化时ROM的预测精度。