Broadband Modal Identification Exploiting the Group-Sparse Characteristic of Aero-Engine Fan Noise Mode

Fan noise is a significant component of aircraft noise, and modal identification is an effective method to analyze duct noise. In recent years, the research on tonal noise has been deepening and maturing, and broadband noise has become a challenge for duct noise research. In this paper, a broadband duct acoustic modal identification method based on a group-sparse strategy and variational Bayesian inference is proposed based on the distribution characteristics of broadband mode. The group-sparse model is used to model the mode distribution, and the mode coefficients and associated parameters are estimated using variational Bayesian inference. The validity of the proposed method is verified through both numerical simulations and experimental tests. The results demonstrate the ability of the proposed method to determine mode coefficients accurately, and the results of the proposed method are also more consistent with the mode distribution characteristics.