Acoustic Scattering By Complex Geometry Using CAA-Chimera Method

Abstract

Acoustic scattering from several complex geometries is simulated using a Computational AeroAcoustics (CAA)-Chimera method. Linearized Euler Equations (LEE) are used as governing equations in solving this problem. The overlapping grids in conjunction with Tam & Webb's high-order central difference DRP (Dispersion-Relation-Preserving) scheme are used to construct so called CAA-Chimera method. The body fitted grid is only used in a very narrow zone close to the curved body. The primary computational grids are Cartesian grids. A multi-domain Cartesian grid system is implemented in which local resolution enhancement is achieved by stepping the grid size of neighboring Cartesian grid blocks by factors of two. In the area of two Cartesian grid interfaces, a combination of DRP and a specially optimized cell-centered high order differencing scheme is implemented not requiring any interpolations. Acoustic scattering from various scatters such as a cylinder or other complex geometry is taken to assess the present methodology in terms of the accuracy of the schemes and the boundary conditions. The effect of body shapes on the scattered acoustic field is also studied.