Identification of aeroacoustic dipole sources of subsonic fan with active acoustic intensity method

Abstract

Various methods have been developed to identify turbomachinery sources based on experimental measurements and signal processing techniques. In the design phase of turbomachinery, aeroacoustic source identification method based on flow simulation is also useful to guide the aeroacoustic design optimization. Wall pressure fluctuation is usually used as the criterion to identify the aeroacoustic sources of turbomachinery operating at subsonic flow, but it ignores the effect of source motion on the acoustic radiation capability. This paper presents a source identification method based on active acoustic intensity to identify the location and strength of dipole sources on both stationary and moving solid boundaries. This method is applied to investigate the aeroacoustic dipole sources of a low-speed mixed-flow fan. Furthermore, the tonal and broadband components of the noise sources are accurately identified by combining the developed source identification method with a pressure triple decomposition method.