Direct numerical simulation of noise and its source from decaying homogeneous isotropic turbulence with particulates

Eulerian-Lagrangian direct numerical simulations of the compressible Navier-Stokes equations are performed for decaying homogeneous isotropic turbulence. Particles are suspended within the turbulent field. A parametric study of over fifty simulations is performed that varies the number of particles and their diameter. The Crighton Ffowcs Williams acoustic analogy is used to predict the noise from the turbulent field with suspended particles. The traditional quadrupole source of Lighthill dominates the radiated noise for low particle number or diameter. As the number of particles or their diameter increase, the root-mean-square pressure scales as the five-halves power of the volume fraction, which indicates that noise is dominated by the monopole and dipole terms. (c) 2021 Elsevier Ltd. All rights reserved.