多参数空间的非线性非定常气动力降阶模型

A Multi-Parameter Space Reduced Order Model of Nonlinear Unsteady Aerodynamics

基于线性卷积和修正因子,发展了一种多参数空间的非线性、非定常气动力降阶模型(ROM),从而高效地获得准确的非定常气动力。首先,基于阶跃响应的卷积构建线性降阶模型;然后应用拉丁超立方抽样得到参数空间内的抽样点,分别计算各抽样点处的修正因子;利用Kriging插值得到整个参数空间内的修正因子,从而得到参数空间内的修正降阶模型。以Isogai机翼为研究对象,考虑马赫数、俯仰振幅、沉浮振幅和减缩频率的变化对降阶模型精度的影响;最后将模型降阶与模型结构方程耦合,进行气动弹性分析并预测颤振边界,由此论证了该降阶模型的有效性。

A multi-parameter space reduced order model（ROM） of nonlinear unsteady aerodynamics is proposed based on the linear convolution and correction factor,to obtain the unsteady aerodynamics accurately and efficiently.Firstly,a linear reduced order model is constructed using the convolution of modal step responses. Then,the nearlyorthogonal Latin hypercubes are used to determine the appropriate sampling points in the parameter space,and calculate the correction factor at each sampling point. Finally,the Kriging surfaces for the correction factor are calculated using the Kriging interpolation method,and the modified reduced order model is obtained. The basic geometric model used for the validation of ROM is the Isogai wing. The effects of the Mach number,sinusoidal input amplitudes and oscillation frequency on the accuracy of the ROM are all investigated. The ROM is coupled with the structural model to make a time-marching simulation,and predict the flutter speed. The validation of the ROM in multi-parameter space is proved by the comparison with results obtained via the high-fidelity computation fluid dynamics solver.