Direct aeroacoustic and aerodynamic simulation of multi-hole engine liners

This paper presents a new method to simulate the aeroacoustics and aerodynamics of engine liners. The method is based on the nonlinear disturbance equations (NLDE). First a steady state flow field is computed by a standard CFL code (or analytically) and then the NLDE is used to simulate the perturbations. Numerically it is fourth order accurate in space and time. Thompson characteristic boundary conditions are applied to introduce acoustic waves at the inlet boundary of the duct. A typical engine liner unit with three holes on the face sheet is studied with and without the influence of a mean flow. The results show the interaction between the holes and their contributions to the acoustics in the duct. This study supplies a better understanding of the mechanism of engine liner aeroacoustics. Parallel computers are a necessity for this compute-intensive problem.