Equivalent Shock-Associated Noise Source Reconstruction of Screeching Underexpanded Unheated Round Jets

This paper investigates the broadband shock-associated noise (BBSAN) radiated from supersonic jets at the root source level. The sources are modeled according to an acoustic analogy. The acoustic-analogy model is informed by high-spatial-resolution two-dimensional two-component particle image velocimetry (PIV) data and solutions to the Reynolds-averaged Navier–Stokes (RANS) equations for the reconstruction of the equivalent BBSAN sources. The measurements are of screeching underexpanded jets issuing from a purely converging nozzle at ideally expanded Mach numbers of 1.45 and 1.59. The jet conditions are simulated using a RANS solver with a k−ω shear-stress-transport turbulence model. The RANS scales are modeled using formulations of a two-timescale model based on the turbulence dissipation and large-eddy-convection time. The large-eddy-convection-based scale is recommended as a replacement for the standard turbulence-dissipation scale in low-order BBSAN models. The equivalent BBSAN sources are reconstruct...