Computation of jet mixing noise due to coherent structures: the plane jet case

摘要: A computational approach to the prediction of jet mixing noise is described. It based on Lighthill's analogy, used together with a semi-deterministic modelling turbulence (SDM), where only large-scale coherent motion evaluated. The features SDM are briefly illustrated in case shear layers, showing that suitable descriptions mean flow and fluctuations obtained. Aerodynamic calculations two cold fully expanded plane jets at Mach numbers 0.50 1.33 then carried out. numerical implementation analogy described different integral formulations compared for jets. shown one expressed space-time conjugate (κ, ω)-plane particularly convenient allows simple geometrical interpretation computations. Acoustic results obtained this formulation relevant experimental data. concluded radiation subsonic cannot be explained by contribution turbulent motion. In case, directivity effects well recovered but acoustic spectra too narrow limited low-frequency range. contrast number 1.33, especially forward quadrant, satisfactory, structures indeed provide main source supersonic noise.