For the first time, this paper presents the sound prediction capabilities of an aeroacoustic wave equation based on Pierce's operator (AWE-PO). The wave equation is applied to a twodimensional mixing layer, providing a solution which is compared with the far-field acoustics of a direct numerical simulation. In contrast to a direct numerical simulation, the computed Lighthill's wave equation and the AWE-PO rely on a hybrid workflow to predict the generated sound. Special attention is put on the visualization and interpretation of the right-hand side of both equations. Finally, the results of the acoustic far-field pressure are compared. It is shown that the radiated sound field's directivity, propagation, and convection effects are captured well for both wave equations. The error of the acoustic intensity compared with the direct numerical simulation is less than 2 dB for Lighthill's equation and AWE-PO. This error is comparable with the errors reported for Lighthill's equation in previous studies. To conclude, the presented wave equation reasonably predicts mixing layer sound, and the acoustic far-field pressure results are in good agreement with the DNS.

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The capabilities of an aeroacoustic wave equation based on Pierce’s operator (AWE-PO) for modeling subsonic flow-induced sound and for sound prediction are investigated. The wave equation is applied to an isothermal two-dimensional mixing layer computed by direct numerical simulation. In contrast to a direct numerical simulation, providing the acoustic fluctuations directly, the simulations based on Lighthill’s wave equation and the AWE-PO rely on a hybrid workflow to predict the generated sound field. Special attention is put on the interpretation of the right-hand side of both wave equations. Comparing the terms on the right-hand side in Lighthill’s theory and AWE-PO suggests a source amplitude for AWE-PO that is 90% smaller. This reduction is attributed to the filtering property of the material derivative. Finally, the results of the acoustic far-field pressure are compared. It is shown that the radiated sound field’s directivity, propagation, and convection effects are well captured for both wave equations. The computations using Lighthill’s equation and AWE-PO are found to provide acoustic intensities within 1.8 dB from the reference direct numerical simulation. This error is comparable with the errors reported for Lighthill’s equation in previous studies.