A Study on Holographic Reconstruction of Cyclostationary Sound Field Based on Boundary Element Method

Abstract

The cyclostationary vibrational signal modulated by other signals can be considered as a special kind of nonstationary signal, which is found frequently in some rotating machinery. The modulation frequency component can be extracted from the total signal using second-order cyclic statistics at the appropriate cyclic frequency. By using the cyclic spectral density functions instead of power spectrum or spectrum as the variables, the cyclostationary nearfield acoustic holography (CYNAH) technique is used to reconstruct acoustic physical quantities in the cyclostationary sound field. In this presented work the CYNAH method is combined with the boundary element method (BEM) to overcome the limitations on the geometries of the planar CYNAH method. The methods used in the conventional BEM-based NAH to overcome nonuniqueness and the ill-posed nature should be also implemented here. The results of a simulation show satisfactory agreement between the computed values and the analytical ones.