Large scale coherent structures in a jet are efficient at sound generation. Interestingly these structures carry a small fraction of the energy in the turbulent field. Our recent study shows how the coherent structures and the radiated sound can be modelled by a linear theory.

Baqui, Y. B., Agarwal, A., Cavalieri, A. V. G., Sinayoko, S.: A coherence-matched linear source mechanism for subsonic jet noise. In: Journal of Fluid Mechanics, vol. 776, pp. 235–267, 2015, (33pp).
A. V. G. Cavalieri, A. Agarwal: Coherence decay and its impact on sound radiation by wavepackets. In: Journal of Fluid Mechanics, vol. 748, pp. 399–415, 2014, (17pp).