Scattering of sound from axisymetric sources by multiple circular cylinders.

A general analytic method for calculating the scattering of sound by multiple rigid circular cylinders arranged in an arbitrary parallel configuration is presented. The sound scattered by this collection of cylinders is generated by a time-periodic, spatially distributed, axisymmetric source located within the domain of interest. A Hankel transform method is used to calculate the incident field, while separation of variables is used to obtain the scattered fields from each cylinder in the collection. The unknown scattering coefficients are determined through the use of general addition theorems that allows the various fields to be readily transformed between coordinate systems. The method is validated using various two-, three-, and four-cylinder configurations, and the number of coefficients that must be retained in the truncated series is examined. Benchmark configurations consisting of two- and three-cylinder systems with cylinders of varying radii are also presented. These solutions have been used to validate computational aeroacoustic solvers developed for complex geometries.