Computation of Time Harmonic Acoustic Waves in a Duct With Nonuniform Mean Flow

The propagation of time-harmonic acoustic and vortical waves in a nonuniform swirling mean flow is studied. A second order accurate numerical scheme is used in solving the linearized Euler equations for an annular duct geometry. A three dimensional ‘exact’ nonreflecting boundary condition is applied downstream of the truncated duct. The numerical issues of implementing the nonreflecting boundary conditions are investigated. Solutions are presented for uniform and nonuniform swirling flows and compared with analytical solutions for validation. The computational results are in good agreement with the theory.