Direct simulation of acoustic scattering by aircraft wings and bodies

This paper extends a recently introduced method to study the scattering of acoustic waves by body surfaces and flow. A special decomposition of the acoustic wave into its incident and scattered parts is used on the whole computational domain. An incident pressure is specified and the associated particle velocities are computed in the absence of the scattering solid. Then the scattered field is calculated taking into account not only the presence of the body but also flow nonuniformity. The solid boundary treatment is handled by the Impedance Mismatch Method (IMM). Use is made of Dispersion Relation Preserving (DRP) schemes for the spatial discretization and a fourth-order Runge-Kutta method is used for the time integration. The boundary points use Tarn and Webb's nonreflecting boundary conditions. Several acoustic scattering problems are solved including acoustic scattering by a two-dimensional cylinder and a Rankine oval, and scattering by a sphere. The programs are written in Fortran 90 and use the MPI library for parallel communications.