The Noise Radiated by High-Speed Jets: Recent Insights From Numerical Simulations (Keynote Paper)

The noise emanating from high-speed jets consists of jet mixing noise and shock-associated noise with its tonal and broadband components. This paper summarizes well-known features of high-speed jet flows and their relationship to the noise radiated by the jet. Open issues on which different opinions exist are also noted. In this context key findings from numerical simulations of jet flows, and model problems related to jet flows are highlighted. The mechanism responsible for the generation of strong screech noise is discussed, and the role of large-scale structures in jet mixing noise and broadband shock-associated noise are stressed. Implications of a new analytical model of shock-cell noise generation are discussed, and in particular the scaling of shock-associated noise from heated jets.