PSE-based prediction of sound radiation by installed jets

A formulation to evaluate the sound generated by a jet in the vicinity of a semi-infinite flat plate based on a PSE (Parabolised Stability Equations) code is proposed. Complexity is added to the model used in Cavalieri et al.,¹ where the flat plate is considered semiinfinite, focusing on the trailing edge scattering of the acoustic source, by exchanging the sound source, previously considered as a semi-empirical wavepacket, for linear PSE solutions, which are based on a linearisation of the Navier-Stokes equations and avoid thus the empiricism of the previous approach. The calculation reproduces the main trends expected for this case, such as the superdirectivity at low polar angles for the free jet and the cardioid shape of the acoustic field for the installed jet, although the amplitudes reached are yet to be validated. We first study the influence of the radial distance between jet and plate, considering that this analysis is only weakly dependent on the two-point coherence of the source. We expect that, although the hydrodynamic field from the PSE has differences in comparison to the semi-empirical wavepacket, the main features observed using the previous model should be identified. This work will lead to a more reliable tool, based on first principles, to study the characteristics of the sound generated by a jet near a trailing edge.