Holographic reconstructions of large-eddy simulations of a highly heated laboratory-scale jet

Abstract

Near-field acoustical holography allows for the reconstruction of a sound field from a limited measurement. For aeroacoustic noise generated by military aircraft, reconstructions of the pressure field within the jet plume have provided insight into equivalent acoustic noise source distributions, though the relationship between these equivalent sources and actual flow pressures and velocities within the plume remain unknown. This study reconstructs the sound field of a highly heated laboratory-scale jet simulated by the Naval Research Lab's Jet Noise Reduction (JENRE) large eddy simulation solver. The simulated data allow for comparisons of the holographic reconstructions of the pressure and particle velocity fields to points along the nozzle lipline, to the Ffowcs Williams and Hawkings integration surface (FWHS), and to the far field. Pressure field reconstructions outside and inside of the FWHS match well, while particle velocity reconstructions follow similar trends as the velocities generated by the LES but severly underestimate the time harmonic complex amplitdues.