Unstructured Grid Solution of the Eikonal Equation for Acoustics

Abstract

An acoustic eikonal equation solution procedure, that is easy to implement in unstructured grid Navier-Stokes equation flow solvers, is outlined. The approach is readily parallelizable. The method is tested for the following canonical point source cases: quiescent flow; subsonic uniform flow; supersonic uniform flow and an idealized jet flow. Then, as further validation, sound propagation of a wave front through a viscous vortex is considered. For these cases, encouraging agreement is found with analytic data and a high-fidelity numerical solution of the Euler equations. Finally, as demonstration cases, the use of the approach to study the shielding of noise from a planar jet is considered along with wave propagation in a complex three-dimensional geometry. At lower Mach numbers (< 0.25), for complex geometries, robust multigrid convergence acceleration is found.