Application of a Discontinuous Galerkin Method to Discretize Acoustic Perturbation Equations

Abstract

Airframe noise of complex geometries, like e.g. high-lift airfoil configurations, may conveniently be computed on unstructured grids. A Discontinuous Galerkin Method (DGM) provides a robust, high-order accurate discretization of systems of partial differential equations like for example the Acoustic Perturbation Equations (APE) even on this type of grid. In particular, a DGM based on Lagrange polynomials may be used, since it enables simple and cheap truncation of flux terms. The goal of the work reported herein is to verify such a DGM. Therefore, the sound field of a monopole situated in a laminar boundary layer is computed. Computations are stable, free from spurious numerical oscillations, and show very good agreement with other computations and with theoretical results.