基于Sobol’法的可变形状空腔全局灵敏度分析

Global sensitivity analysis of a deformable cavity based on the Sobol’s method

高速气流经过空腔结构产生的高强度空腔噪声极易诱发空腔内结构共振而导致腔内元器件声疲劳破坏。提出了一种可变形状空腔控制方法,该控制方法通过机械装置调节空腔前、后壁面的倾斜角度达到降低空腔噪声的目的;在Ma=0.85条件下,利用大涡模拟(LES)预测空腔内的流体流动,以可变形状空腔的前、后壁面的倾斜角度作为设计变量,以空腔底板表面噪声载荷的主模态幅值作为响应,利用基于MSE准则的Kriging方法建立二自由度可变形状空腔的代理模型,利用Sobol’法分析模型的全局灵敏度。发现,可变形状空腔的前、后壁面倾斜可以明显抑制空腔底板表面噪声载荷的主模态幅值,其中后壁面倾斜的全局灵敏度为前壁面倾斜的1.712倍,并且前、后壁面倾斜对空腔底板表面噪声载荷的主模态幅值的交互影响小。

The high-intensity cavity noise generated by the high-speed airflow passing through the cavity structure can easily induce the cavity structure resonance and lead to the acoustic fatigue damage of the components in the cavity.Therefore,a deformable cavity control method was proposed,which can reduce the noise of the cavity by adjusting the tilt angle of the leading and rear wall of the cavity with mechanical devices.At the Mach number of 0.85,a large eddy simulation(LES)was used to predict the fluid flow in the cavity.Taking the inclination angles of the leading and rear wall of the deformable cavity as design variables and the main tonal noise as the response,a surrogate model of the deformable cavity was established using the Kriging method based on the MSE criterion,and then the global sensitivity of the model was analyzed by the Sobol’s method.It is found that the leading and rear wall tilt of the deformable cavity can significantly suppress the main tonal noise,the global sensitivity of the rear wall tilt is 1.712 times that of the leading wall tilt,and the interaction effect of the leading and rear wall tilt on the main tonal noise is small.