Experimental characterization of acoustic pressure waves propagating in circular ducts

The increasing interest in thermoacoustic phenomena in turbomachinery components prompted a detailed analysis of acoustic field propagation in ducts. The numerical codes for the prediction of the acoustic behavior of complex system are still in a developing phase and an experimental validation is still necessary. The wall acoustic pressure could be easily measured whereas very few examples of radial measurement, necessary for a 3D analysis, are present in the literature. In this paper, several simple remote probes mounting a ¼" pressure microphone were characterized. The one that performed best, was used to map the acoustic pressure field of a wave propagating in a circular duct with different modes. The experimental set up and the calculation methodology are shown in detail in the paper.