ソニックインレットの研究

抄録

In recent aircraft with high by-pass ratio engines, the major noise source is the forward propagating fan noise from the engine inlet. Reported here is the investigation of the sonic inlet, which drastically reduces the abovementioned forward propagating fan noise. Model sonic inlets of both contracting wall type and translating centerbody type were designed by the newly developed analytical method based on flux analysis, and tested aero-dynamically and acoustically. Criteria for boundary layer separation, total pressure recovery characteristics, and crosswind characteristics of sonic inlet were obtained, and the model sonic inlet of the contracting wall type showed 21 PNdB noise reduction in model engine noise tests. Comparison between the analytical and experimental results proved the usefulness of the newly developed design method.